DENVER -- The justice system failed 10-year-old Ty Tesoriero, a Lone Tree boy murdered at the hands of his own father, and Rep. Jonathan Singer, D-Longmont, said he wants to prevent further heartbreak for Colorado families.

"We're going to get justice. It's going to be too late for Ty, but it's not going to be too late for the next kid if we pass this bill," said Singer.

Domestic violence abusers with protection orders are supposed to surrender their weapons under Colorado law, but Contact7 Investigates found the law isn't working as intended.

Anthony Tesoriero, who shot his 10-year-old son, Ty, and then killed himself, is one of those abusers who never should have had a gun, but clearly did.

The murder-suicide happened in Lone Tree back in September and came hours after Ty's father learned he was going to lose custody of his son.

"He was not supposed to have a weapon," Ty's mother, Jing Tesoriero, said back in September. "I don't want this to ever happen again."

The law states domestic abusers with protection orders must turn over their firearms within 72 hours and notify the court. Fail to do so, and "the court shall issue a warrant for the respondent's arrest."

What the law doesn't say is who is responsible for making sure that happens.

HB-1278 would close the loophole in Colorado's gun law by requiring courts to talk to cops and give domestic violence offenders three options for relinquishing their firearms under the law.

Offenders could give their weapons to their local sheriff office for storage, hand them off to a licensed fire arm dealer, or a person of trust who passes a background check. An amendment to the bill proposed Tuesday during a committee hearing would also give offenders immunity from further prosecution.

"It says, 'Look, if you follow the law, we're going to give you immunity, we're not going to prosecute you for following the law," explained Singer.

The National Rifle Association (NRA) and Colorado County's Sheriff both expressed strong opposition to the bill Tuesday.

Concerns raised included the fact domestic violence offenders would be required to turn over their guns during first appearances in court, potential violations of Fifth Amendment rights, and how much it would cost for sheriff offices to store these weapons. The bill sponsors, however, have said they are willing to legislate funding into the bill.

"It's time that Colorado start enforcing the laws on the books when it comes to domestic violence," said Singer. "We know that guns and domestic violence are a deadly mix."

A public health nurse and neighbor who lived near the apartment where Ty's father killed him also testified in support of the bill.

"I saw Ty that night," said neighbor Holly Cheng. "My son was friends with him, played with him every day, I mean -- it has impacted us in every way," she said.

Cheng, who also works with domestic violence survivors, said she was testifying to change the system that failed Ty and other survivors.

"I would never be here today if Ty wasn't killed," she said.

Ty's mother, Jing, was not able to attend the hearing because she was out-of-state, but told Denver7 she supports the bill and enforcing a law that could have prevented her son's death.

The bill was heard in a house committee for several hours Tuesday, and was put on pause while lawmakers draft new amendments before bringing it back to committee.

Meanwhile, Ty's mom, Jing Tesoriero, has been pushing for even more changes including to Colorado's family law court system which allowed her son to go home with his father for one last night before losing custody. Other lawmakers are looking at legislation that could potential address those issues.