The following script is from "Confidential Informants" which aired on Dec. 6, 2015. Lesley Stahl is the correspondent. Shari Finkelstein, producer.

When many of us hear the term "confidential informants" -- or as law enforcement calls them, C.I.s -- we think of mobsters wearing a wire to ensnare their bosses, and get themselves a better deal. But there's another kind of confidential informant out there that doesn't quite fit the Hollywood image, and in reality may be far more common: young people -- many of them college students caught selling small amounts of marijuana, who are recruited by law enforcement to wear a wire and make undercover drug buys in exchange for having their charges reduced or dropped altogether.The

It's a practice we discovered that's going on across the country, largely under the radar -- and in some cases, with tragic consequences.

[Jason Weber: How's it going today?

Andrew Sadek: Alright.

Jason Weber: It's your birthday today?

Andrew Sadek: Yeah.

Jason Weber: Probably not what you want to be doing on your birthday, huh?

Andrew Sadek: (shakes head)]

What you're looking at is police footage of the making of a confidential informant. Narcotics officer Jason Weber is recruiting a college student who'd been caught making two small marijuana sales, to become a C.I.

Andrew Sadek, left, and Jason Weber CBS News

[Jason Weber: Alright well you expressed interest that you probably want to help yourself out.

Andrew Sadek: Yeah.

Jason Weber: We're always trying to go up the chain. And so what we want to do is have them buy from their supplier, or suppliers.]

Weber is the chief of a four-county drug task force in eastern North Dakota and western Minnesota.

Lesley Stahl: How important do you think confidential informants are to your task?

Jason Weber: Yeah, confidential informants are really important to law enforcement across the country. They make our jobs easier just because they are already the ones that are out there that know who the drugs dealers are and rely on them.

Lesly Stahl: Are most of the kids that you're recruiting caught for marijuana sales?

Jason Weber: The big majority, yeah.

Weber's jurisdiction includes the campus of the North Dakota State College of Science, with some 3,000 students. Marijuana is now legal in four states and the District of Columbia, but not in North Dakota, where selling even a small amount on a campus is a Class A felony, with a maximum sentence of 20 years in prison, a fine of $20,000, or both.

This young man, Andrew Sadek, was caught on tape by another confidential informant making two sales -- for a total of $80. Weber has called Sadek in before charging him to present a choice: agree to work as a C.I., wear a wire and make undercover drug buys from three people, twice each -- or be charged with two Class A felonies.

[Jason Weber: Potentially the max is 40 years in prison, $40,000 fine. You understand that?

Andrew Sadek: Yeah.

Jason Weber: OK. Obviously you're probably not gonna get 40 years, but is it a good possibility that you're gonna get some prison time, if you don't help yourself out? Yeah, there is, 'k? That's probably not a way to start off your young adult life and career, right? (Sadek nods)]

Sadek took the deal. Weber told us most students do. Part of the agreement he signed: keep the whole thing strictly to himself.

Jason Weber: You can't tell anybody you're working for me. Obvious -- for obvious reasons. (Sadek nods)]

An award-winning student of electrical technology, Andrew Sadek did as he was told: never told any of his close friends about being an informant; never called a lawyer; and didn't breathe a word to his parents, Tammy and John Sadek. The Sadeks are a ranching family still struggling with the death of their older son in a train accident years earlier, leaving Andrew an only child.

Lesley Stahl: If Andrew had told you that he was thinking of becoming a confidential informant, what do you think your reaction would've been?

Tammy Sadek: We'd have gotten him a lawyer and told him, "No."

John Sadek: We've never heard of such a thing, ya know -- using college students for snitches or whatever you wanna call 'em, stool pigeons, or I don't know what you call 'em, you know?

Lance Block: There's no parent that I know of who would allow their child or want their child to serve as a confidential informant.

Lesley Stahl: To set up a drug deal --

Lance Block: Yeah. I mean, it's too dangerous. No, I wouldn't want my child to do it.

Lance Block is an attorney in Tallahassee, Florida, who opposes using young people caught for relatively minor offenses as confidential informants.

Lance Block: These kids are being recruited to do the most dangerous type of police work. They're going undercover, with no background, training, or experience. They haven't been to the police academy.

Lesley Stahl: So they are basically doing the same work as a trained undercover cop?

Lance Block: Absolutely.

Block says he was unaware police were using young people as confidential informants until he was hired seven years ago by the family of Rachel Hoffman, a recent college graduate who was caught with a large stash of marijuana and a few Valium and ecstasy pills. It was her second marijuana arrest.

Rachel Hoffman

Lance Block: She was caught by the Tallahassee Police Department and told that if she didn't become a confidential informant, she was looking at four years in prison.

She signed up, and a few weeks later was sent out to make her first undercover drug buy. It was to be one of the biggest in Tallahassee's recent history -- 1,500 ecstasy pills, an ounce and a half of cocaine, and a gun.

Lesley Stahl: Had she ever dealt in any of those things?

Lance Block: No.

Lesley Stahl: A gun? Had she ever fired a gun?

Lance Block: No.Rachel was a pothead. And Rachel sold marijuana to her friends out of her home, but Rachel wasn't dealing in ecstasy or cocaine, much less -- of course not weapons.

Rachel drove her car alone to meet the dealers in this park with $13,000 cash from the police and a wire in her purse. She was to be monitored by some 20 officers. But then the dealers changed the location of the deal, so Rachel drove away from the police staging area, and that's when things went terribly wrong.

Lance Block: The drug dealers have her out on this road. One drug dealer gets into the car with her --

Lesley Stahl: And the 20 cops who were nearby?

Lance Block: They lost her.

[Newscaster: Hoffman is 5'7", 135 pounds. She was last seen...]

[Newscaster: Hoffman was seen Wednesday night at about 7 o'clock near Forest Meadows Park.]

Lance Block: They shot her five times when they found the wire in her purse and dumped her body in a ditch 50 miles away.

Rachel Hoffman's tragic death turned Block into an advocate. He sued the City of Tallahassee and won a $2.8 million settlement for Rachel's parents, and he has argued for more openness and greater protection for confidential informants ever since.

Lesley Stahl: Do you have any sense of how many confidential informants there are?

Lance Block: Law enforcement is loaded with statistics. But you cannot find out any information about the number of confidential informants that are being used across this country, much less the number of people who are being killed or injured.

Lesley Stahl: No one's keeping statistics?

Lance Block: No one. It's a shadowy underworld, is what it is.

[Brian Sallee (lecture): We want to make more cases. We want to make better cases that can get prosecuted. Informants can do that.]

Brian Sallee is a longtime undercover narcotics officer who believes a shadowy underworld is exactly what working with C.I.s should be -- shadowy to protect informants' identities, and underworld because that's where cops like him want informants to take them.

[Brian Sallee (lecture): Who knows the most about the dope trade? Is it us, working narcotics? No. Who is it? The sellers, the dopers.]

Sallee says he's worked with hundreds of informants, and now trains police officers around the country on how best to use them.

Lesley Stahl: If you had not been able, personally, to use confidential informants, would you have been as effective?

Brian Sallee: Nowhere near as effective.

Lesley Stahl: You really feel you need this --

Brian Sallee: Oh, I know I would not. I may have to watch a house for days or weeks to establish probable cause. My informant goes in and makes a buy-out of it, and I have my probable cause in five minutes. You can get into cases quicker, easier -- in some respects, safer.

Lesley Stahl: I'm surprised you say safer, because we've heard about kids who've been killed doing these operations.

Brian Sallee: It's a dangerous trade that they're involved in.

Lesley Stahl: Yeah.

Brian Sallee: They are in that drug trade. They've always been facing that potential danger.

Sallee estimates there could be as many as a hundred thousand confidential informants working with police across the country, and he says with just a few tragic exceptions, it's a win/win -- a win for society, and a win for the C.I.

Brian Sallee: They have agreed to do what they are doing in exchange for something. That's the bottom line. When somebody comes to work for me as an informant, it's their decision.

Lesley Stahl: Police tell us that this is completely voluntary, and they want to do this to get rid of the charges.

Lance Block: It's not something that college kids are standing up, saying, "I wanna be a CI." It's not voluntary. They're being told they're looking at prison time unless they agree to do deals for the police department.

And there are some important things they're not being told.

Lesley Stahl: So what if you catch me selling $60 worth of marijuana? What do you say to me to become an informant?

Brian Sallee: I'll say, "This is the charge.This is a felony. Do you want to help yourself out?"

Lesley Stahl: Do you tell me that I have a right to talk to a lawyer?

Brian Sallee: No. I do not. I tell you you have a right to talk to a lawyer if I'm going to ask you incriminating questions. If we're talking about your becoming an informant, I don't have to tell you that you have a right to a lawyer.

That's because, since police often recruit confidential informants before charging them and without arresting them, they're not obligated by law to read them their rights. And agent Jason Weber didn't with Andrew Sadek.

He told us Sadek made three successful undercover drug buys as a C.I., half the number he'd been told was required of him, but then he stopped. Weber says Sadek was warned he would soon be charged if he didn't continue. Then one night a few weeks shy of graduation, security cameras snapped these pictures of Sadek walking out of his dorm at 2 a.m. on a Thursday morning. A day and a half later, he had not come back.

Tammy Sadek: We got a call from the campus at about noon on Friday.

Still completely unaware of their son's work as a confidential informant, Andrew's parents were soon on campus, making a public plea for his return.

[Tammy Sadek, press conference: We love you, and we want you-- we need you to come home.

John Sadek, press conference: Everything will be OK.]

There were searches, prayer vigils. And then, two months later, the worst news possible -- Andrew's body was discovered in a river near the campus, his backpack weighted down with rocks, its straps tied together across his chest.

Lesley Stahl: Did they tell you what the cause of death was?

Tammy Sadek: Gunshot to the head.

A year and a half later, that's about all the Sadeks have been told. No one has been charged in Andrew's death, and the gun that killed him has not been found. Police deny he was involved in any C.I. operation the night he disappeared and have suggested to his parents that he may have shot himself, a possibility they say is inconceivable. They're convinced their son was murdered as a result of his work as an informant, and they want the confidential recruitment of young offenders as C.I.s to stop.

Tammy Sadek: It's ridiculous. Ridiculous. Stop doing it. Slap their hands. Fine 'em. Put 'em in jail. Expel 'em. I don't care. Stop using our kids to do your jobs.

Andrew Sadek's death is still an open investigation, so neither the state agencies in charge of the case, nor Jason Weber, would talk about it. But we did ask about putting these kids at risk.

Lesley Stahl: Andrew Sadek was caught selling $80 worth of marijuana. People have said to us, "It's just not worth it. It's not worth putting the kid in any kind of risky situation for that little."

Jason Weber: You know, a drug dealer is a drug dealer whether you sell a big amount or a small amount, whether you do it once or if you do it 100 times. While it's still against the law, part of our duty as law enforcement is to get the drugs off the streets and to get the drug dealers off the streets.

Lesley Stahl: So how successful is what you're doing?

Jason Weber: Well I think it goes back to the point, if we don't try something or if we don't do that, then we're truly losing that -- the war on drugs.

Lesley Stahl: Isn't it more important to go after heroin, meth, cocaine?

Jason Weber: Yeah, our agency goes after all them.

Lesley Stahl: I'm still trying to get at the equation, you know what I mean. Is it worth it, for marijuana?

Jason Weber: Yeah. There again, I gotta go back to, you know, as long as it's a crime, it is my duty as a police officer to enforce criminal law.

We've spoken to college students who talk about how they were pressured into becoming confidential informants.

Greg: It felt like I had a gun to my head.

That part of the story, when we come back.

Part Two

We wanted to know what the law is across the country about the use of young people as confidential informants -- and we were surprised to discover that in all but a handful of states, there is no law. No age limits on who can become a C.I., no rules about how, or even whether, informants must be trained, no guidelines on their protection.

Policies are typically left up to the individual police departments that recruit and use the informants -- and that, critics say, can and has resulted in overly aggressive recruitment tactics, traumatized and even suicidal C.I.'s, and situations where kids are given incentives to entrap other kids.

We looked at a case, a narcotics unit where those charges have been leveled. It's in one of the country's best-known college towns, with the university itself an involved partner and funder.

The University of Mississippi in Oxford -- famously called "Ole Miss" -- is known for its football, its school spirit, and its Southern charm. But less than a mile from campus, housed in this municipal building, is a drug task force focused on the darker side of life here. It's called Metro Narcotics, and one of its confidential informants was an Ole Miss student we'll call Greg, who agreed to speak with us in disguise. His life as a C.I. began one day coming home from class.

Greg: I was met halfway there by men in bulletproof vests, guns and badges around their necks. My initial reaction was just "Keep goin'. This is no way involved with me." And then -- until they held up a piece of paper with my name on it, saying I had sold LSD, and I thought, "What on earth? I had nothing to do with this."

Greg, who had no criminal record, insists his only encounter with LSD was when a friend asked to leave some at his apartment. Then, he says, another acquaintance stopped by -- wearing a wire, it turns out -- and picked the LSD up.

Greg: I was just on the couch watching TV. And he was like, "Oh, thanks." And I just said, "I have nothing to do with this. Don't thank me."

But at the metro office, Greg says two agents threatened him with more than 20 years in prison and a felony on his record for life, unless he agreed to become an informant and make drug buys wearing a wire from 10 people -- who he had to find himself.

Greg: It felt like I had a gun to my head.

Lesley Stahl: Have you told them yet that you had nothing to do with this?

Greg: They almost convince you that -- that you're guilty. I was just so scared, I was just putty in their hands.

Lesley Stahl: Did you think about the idea that you'd become a snitch?

Greg: I mean, I knew what I was signing and I hated it, absolutely. It just made me sick, but what made me more sick was the thought of spending 20 years in prison.

Lesley Stahl: Did you know 10 people you could buy drugs from when you signed that paper?

Greg: Absolutely not. But you don't care at the time, when you sign it. It's like, "Sure. You know, please don't ruin my life."

Lesley Stahl: Ten buys sounds like a lot.

Ken Coghlan: It's virtually impossible.

Ken Coghlan is a defense attorney in Oxford who has represented many Ole Miss students who became confidential informants. He says because there are no standardized rules, cops can ask for any number of buys -- like Metro's 10, which he says is so high, it creates a perverse incentive for kids to entice other kids to break the law. He told us he has seen it again and again.

Ken Coghlan: They don't know 10 drug dealers. And they're so desperate, they will go to their friend or their roommate or their frat brother, and they know this person smokes marijuana. And they'll say, "I'm out of weed. Can I get 10 dollars' worth of weed from you?"

Lesley Stahl: Your personal stuff.

Ken Coghlan: That's entrapment. And that's not allowed under the law.

Entrapment, because that frat brother with his own marijuana was only guilty of possession -- a misdemeanor under Mississippi law; but if he says yes and sells a little to his buddy, he's now become a dealer -- a felon, facing possible prison time.

Ken Coghlan: And at that point we're not catching criminals, we're creating criminals.

Lesley Stahl: Did you ever get the feeling that you were asking someone else to commit a crime that they wouldn't otherwise have committed?

Greg: Yes. I just knew somebody who would provide me with an amount who wasn't selling, but I just knew they, they would 'cause we knew each other.

Lesley Stahl: And you did that?

Greg: Yes.

Lesley Stahl: So when you say they're creating felons, this is what you mean?

Ken Coghlan: I don't think the cops say, "Go out and talk somebody into doing it that wouldn't otherwise do it." It's just what the kids do. And look there-- there are some hard drugs around. But the vast, vast majority of cases are sale of two grams of marijuana, three grams of marijuana.

But those small sales can add up to big numbers of arrests -- and numbers, says Tallahassee attorney Lance Block, help drug task forces get grants.

Lance Block: They wanna drive up their arrest numbers. And it doesn't matter whether they're going after a college kid with a couple of joints in his pocket, or whether they're going after a drug kingpin.

Lesley Stahl: And the more arrests, the more money?

Lance Block: The arrest numbers, the higher they go, the better the funding. I mean, law enforcement is addicted to the drug war money as the crack addict is on the street to his drugs.

It's a strong charge. We put it to undercover narcotics agent and instructor Brian Sallee.

Lesley Stahl: What they say is that police are in this to lift their arrest statistics to justify the grants and money that they're getting.

Brian Sallee: I'm in it to do what is best for my community. And if having higher stats gets me more money and allows me to do more cases to then impact the drug trade in my community, then that's also a benefit.

Metro Narcotics got nearly $55,000 in federal grants last year, but most of their budget comes from the city police, the county sheriff's department, and Ole Miss: $100,000 each. The head of Metro Narcotics for the last five years has been Keith Davis, seen here on an Ole Miss student newscast defending his unit's work with students as informants.

Keith Davis: These are adults, these are 18, 19, 20 year olds. Yes, I get it -- they have young minds, whatever. But they are out here creatin' felonies and hurting our communities.

We requested our own interview with Davis, or any representative of Metro Narcotics, but they declined. One thing we wanted to ask Davis about were charges that he and other agents in the unit were abusive to the C.I.'s.

Greg: They call you and in these calls, they're very aggressive and threatening and saying, "Well, we're going to come pick up and you're gonna go to prison," to the point where I was just terrified whenever my phone rang.

We heard similar claims from another Ole Miss student who became a confidential informant after Metro Narcotics accused him of selling marijuana.

Bob: They say your life is over if you as you know it, if you tell anybody, if you don't help us.

Lesley Stahl: Did they specifically say, "You can't call your parents?"

Bob: They said, "If you call your parents, we'll take you to jail."

Once he agreed, he says one of the first things the agent asked him was whether he could buy meth or heroin. He told him he couldn't.

Bob: The first eight months or so, he called every single day at around the same time.

Lesley Stahl: He called you every day for eight months?

Bob: Every day.

We had heard repeated accusations about the aggressive tone of the Metro agents, and then got to listen for ourselves, when we obtained a tape recording of Keith Davis and another Metro agent yelling at a C.I. recruit they heard had made a threat to find out where they lived. The first voice is that of agent Tommy Knight.

[Tape recording:

Tommy Knight: I don't give a f*** where you at.

Kid: Yes, sir.

Tommy Knight: I'll turn this s*** in and I'll come beat the f*** out of you.

Kid:Yes, sir.]

Lesley Stahl: Whoa.

The tape was made surreptitiously by the C.I. recruit who brought it to Ken Coghlan. We listened with him as Keith Davis made his own threat if the kid ever went to his house.

[Excerpt from audio recording

Keith Davis:Come there -- it'll be the last f****** place you ever go in your life.

Kid: Yes, sir.

Keith Davis: You feel me?

Kid: 100 percent.

Keith Davis:It took all I had not to come see you last night.

Kid: Yes sir.

Keith Davis: To hunt you down. But I'm trying to calm down.]

Lesley Stahl: Keith Davis is the chief of this narcotics unit, and he is making a death threat.

Ken Coghlan: You know, I'm just gonna let the tape speak for itself.

Coghlan sent the tape and a letter to the chancellor and attorney of Ole Miss more than two years ago, thinking that as a funder of Metro Narcotics, they should know how the unit was treating its students. He got no reply and we could find no evidence that changes were made to the program at the time.

Greg told us that as he continued making undercover buys he became anxious and paranoid.

Greg: I would have to conceal that I was shaking, because first of all, I completely detested what I was doing. I didn't wanna get anybody in trouble.

Lesley Stahl: Did you feel ashamed?

Greg: Absolutely.

Lesley Stahl: Because of turning in other kids?

Greg: Yes.

But Keith Davis told the Ole Miss campus reporter that these kids don't deserve that much sympathy.

Keith Davis: Let's be clear here: these people are not these innocent little college kids, plain and simple. The ones that are selling dope are not innocent people. They're selling poison.

That may be true for many confidential informants, but it turns out, not Greg. After a year and a half -- and he says making six of the 10 required buys -- Greg was charged and arrested anyway. That's when his parents found out and hired Coghlan, who researched the original evidence against Greg and came to the conclusion that the friend who brought the LSD to Greg's house in the first place had been a C.I.

Lesley Stahl: So a C.I. brought the drugs. And a C.I. bought the drugs.

Ken Coghlan: That's the way I understood it to be.

Coghlan says after he brought the situation to the attention of the district attorney, the charges against Greg were dismissed.

Lesley Stahl: All the charges were just thrown out?

Greg: Completely.

Lance Block: It's really important that the public have an understanding of what's going on, because it's perverted justice.

Lesley Stahl: I've been told that a lot of these kids are not really looking at jail time.

Lance Block: In the vast majority of cases, these kids would be diverted into a drug court program. They'd be on probation for six months to a year, and at the end, if they've done everything successfully, then the cases are dismissed.

Lance Block has been advocating for laws to regulate the recruitment and use of confidential informants across the country, but he says law enforcement lobbies have opposed the reforms.

Lance Block: They want to keep the C.I. system as it is.

Lesley Stahl: Law enforcement people have told us, "We see it as a win/win. The kids get a reduced or charges completely expunged, and we get to arrest drug dealers."

Lance Block: But there are kids that are being killed. And they're arresting small-time possessors. That's a lose/lose.

We asked Ole Miss for an on camera interview while we were reporting our story. Our request was declined. We did get a letter months later saying, quote: "thank you for your part in encouraging a deeper look at the Metro Narcotics Unit," and telling us that because of "increased attention" - attention from 60 Minutes and the news organization BuzzFeed, changes were being made, including: "more direct oversight of the program," "an audit of the program...by a third-party organization," "policies to ensure suspects fully understand they have a choice in whether to become a confidential informant;" and a change in the leadership. At the end of September, Keith Davis resigned as head of the unit. He now works for the sheriff's department.