TAMPA — Kenneth Spain told his students at Chamberlain High School that he overcame a pornography addiction when he found Jesus.

Pornography and Jesus are both taboo topics for public school teachers, so this became a case for the Hillsborough County school district's professional standards office.

Spain resigned. He asked if he could return as a substitute. A letter in his file said not just yet.

But Kelly Educational Staffing hired him anyway and sent him to work at Greco Middle School.

Kelly — contracted by the district since 2014 — fills more than 170,000 shifts each year when teachers are absent or on leave.

Its ranks include hundreds of former Hillsborough teachers. While some are retirees, others were fired or resigned amid allegations of wrongdoing, a principal's low opinion of their teaching abilities or because they lacked proper certification.

A Tampa Bay Times investigation found reports of substitute teachers sleeping on the job, calling children "idiots" and "retarded," making sexually suggestive comments and lashing out against school staff — sometimes even stealing from them.

Children in the lowest-income schools are often the most likely to spend their days with substitutes. These include the seven "Elevate" schools that Superintendent Jeff Eakins designated two years ago to receive the best resources the district had to offer.

Officials from Kelly and the district said the problems cited by the Times are aberrations. They said the vast majority of substitutes do a good job and the arrangement, which costs about $13 million a year, has improved a longtime struggle to fill vacancies. They said the relationship is evolving and improving over time.

But the superintendent acknowledged gaps in the process, which became less transparent when the task was outsourced.

On Dec. 20, he sent a letter to Kelly asking about employee discipline and for more information on the substitutes brought to his attention by the Times. If company officials fail to respond, he will consider them in violation of their contact.

"I don't have a lot of patience for people who, with our kids, conduct themselves unprofessionally," Eakins told a reporter.

• • •

It took nearly four months for the Times and its attorney to obtain the incident reports principals submit when they have a bad experience with a substitute — the very reports that, when later seen by Eakins, inspired his letter.

Kelly initially refused to provide any information about its employees and turned down the Times' request for the so-called "Do Not Use" forms. The district gave the same response to ABC Action News when it reported in April on a substitute teacher accused of masturbating at Shields Middle School.

Kelly finally turned over 443 forms after the district's attorney agreed that the company is doing public business and therefore should comply with state disclosure laws.

The forms, covering roughly half the time the Kelly contract has existed, describe substitutes yelling at 5-year-olds and lashing out at staff, even asking a department head to fetch coffee.

There were dozens of examples of inappropriate speech — saying children belonged in the zoo or would wind up in prison, calling them "ghetto" or using the "N" word. One teacher, when a student complained that the music was too loud, allegedly threatened to raise it and hold the student's ear against the speaker.

There were sexually suggestive comments. A substitute was described stroking himself. A child was told she had "a stripper name."

A substitute spent his entire shift at Essrig Elementary School weeping uncontrollably. Another, unable to get to Benito Middle School on time, sent his twin in his place. One teacher, on multiple occasions and at multiple schools, bled all over the floor from an injured foot.

A substitute was seen at Bryan Elementary School "wandering around campus like she's lost and cannot remember where she dropped students off." Another "almost passed out" at Adams Middle School and had to be driven to the bus stop. A teacher at Brooker Elementary slapped a child to wake him up from a nap.

And more than a dozen were described napping in class themselves.

Some gave the children disturbing assignments — to draw women in bikinis or, in one class at Buchanan Middle School, "a dog eating a cat, or a cat eating a dog."

Rooms were trashed. Teachers returned to find their food eaten, belongings gone. One had $30 stolen from her purse.

"There has to be a better way of screening these individuals," Pride Elementary teacher Hannah Rogers wrote after a substitute did not follow the lesson plan, did not know to walk the children to lunch and had trouble speaking English.

"They need to realize they are coming into a classroom to teach students. Not sit at a desk to babysit. I shouldn't feel uncomfortable when I am sick or when my daughter is sick to call in for a substitute."

Kelly continued to use that substitute at other schools.

Donna Ippolito, the principal of Burney Elementary School, spent much of Oct. 16, 2015 contending with an angry substitute who, according to her description, berated a class of fourth-graders. He then turned on Ippolito, who had checked on the class after a parent recognized the substitute and called to complain.

Much of what the substitute said was incoherent, according to Ippolito's letter, though he threatened, "I'm calling 911." He left campus, then returned, still irate, to pick up his jacket. He did not calm down until he saw that a security officer was in the front office. Ippolito wrote that she was concerned because a Kelly supervisor gave her the impression that the man might still be assigned to another school.

That did not happen, according to payment invoices reviewed by the Times. In fact, the invoices suggest many of the substitutes were dropped after Kelly received complaints. These include a substitute who told students at Blake High School that "homosexuality is a disease" and, days later at Strawberry Crest High, attached sticky notes with Bible verses on the backs of the teacher's personal photos.

The substitute denied it, but staff at the school identified him using handwriting samples. He is one of the dozens named in Eakins' letter, which seeks clarity on how Kelly handled those situations.

Another substitute, described as having "a bad attitude" at Randall and Burnett middle schools was invited soon after to teach at Mulrennan, Tomlin, Turkey Creek, Giunta and Marshall.

A substitute worked most of September 2015 at Burnett Middle even though the previous April, she was accused of hitting a child with her cane.

As for the teacher who was said to have asked children to draw cats and dogs eating each other?

He filled a vacancy at Pierce Middle School for the first months of 2016.

The forms gave the name, but no details, about a substitute at Potter Elementary whose case was discovered during a separate Times investigation in 2016. That substitute, according to statements to Tampa police, threatened a class of fourth-graders after some called him "gay" while his back was turned. Children said he told them he was from the streets and had a gun.

And the Times received no documentation about the incident at Shields that prompted the television story, about a teacher accused of masturbating in class. There is, however, a lengthy report on file at the Hillsborough County Sheriff's Office.

In both the Potter and Shields cases, there were no arrests. Records show Kelly stopped using both employees.

In response to the television story, the district this school year began requiring principals to copy the human resources office on all Do Not Use forms. That has helped the district get a jump on problem situations, Eakins said.

In August, personnel services manager Dena Collins told the Times that it had not been her practice to review the forms. She believed they were often about minor issues, such as a teacher wearing jeans to work. Instead, she relied on frequent conversations with Janelle Weaver, Kelly's area manager, to work out issues of concern.

In November, when Eakins saw the forms that the Times requested, he realized how many issues were slipping through.

And so, while insisting most of the problems are "historic" because of the new protocol, Eakins said he also is taking a hard line with the company. "We can't have any gaps," he said.

"There's got to be a level of confidence that I have to have that all of these cases are being handled in a way that we would want them to be handled."

• • •

Comparisons between the current system and the old system, in which the school district hired and supervised its own substitute teachers, are difficult, partly because much of the administration has turned over in the last three years.

District leaders and Kelly officials, who ultimately took part in an interview with the Times, say the outsourcing arrangement is overwhelmingly successful. "Fill rates" have improved from as low as 60 percent to an average of 85 percent. At schools that historically had the most trouble, Kelly addresses that problem by recruiting in the community.

While higher fill rates equate to more money, district leaders point out that under the old system, they paid more to staff teachers who had to cover extra class periods.

Eakins hopes to strengthen oversight through his ongoing communication with the company.

Kelly leaders say their substitutes include onetime principals, professional athletes and highly educated military spouses. More than 300 transition each year to full-time teaching jobs, making Kelly an important recruiter for the district.

"People we are finding are passionate about teaching," said Kelly territory vice president Adam Watkins. "They want a career change, or have been teachers and want to continue on that path. This is a great avenue for that."

Some Kelly recruits are rejected after criminal background checks, with standards that correspond to those used by the district. Those hired — the district considers 2,500 to be "active" — earn between $8 and $11.25 an hour, depending on their qualifications, after a 33 percent markup to the company.

A half-dozen former district administrators, now working for Kelly, serve as mentors. The company provides training in ethics and classroom management, using district methods and personnel. It offers tips on how to become a certified teacher.

"When you look at the percentage of incidents that occur, I wish you had the number of positive things that occur, because it would certainly outweigh the negative," Collins said. "On any given day 800, 1,500 classes have substitutes."

Kelly's managers said that when a complaint comes in, they investigate and take action if the allegation is supported. The substitute might get a counseling session. "A first and final," it is sometimes called. Sleeping on the job is one of the easiest infractions to prove, as "we get pictures," Weaver said.

"Our goal is to make sure we have professional people in the classroom," Watkins said. "So we vet as hard as we can in the circumstances that we have. We can't run them through a day in the life for a week, try them out and watch them. It's just impossible."

But it is possible to research the work histories of the district's former employees.

Collins said she provides an "alert list" that Kelly consults to avoid hiring educators with records of misconduct.

"If we won't hire them," Collins said, "then I'm not going to have them hire them."

Yet teachers have slipped through.

Records show Kelly sent Calvin Cyrus to eight middle and high schools in November and December of 2016 even though his resignation papers on Nov. 1 said he could be rehired only for a "noninstructional" job.

A student at South County Career Center had accused the 54-year-old Cyrus of grabbing him by the neck during an altercation that escalated when he poured water on the teacher's desk.

Cyrus told investigators the student lunged at him and, as he tried to defend himself, briefly touched the student's shirt.

Kenneth Spain's file also signaled he was not ready to return to the classroom.

An email in January 2016, shortly after the pornography remark and his resignation, said he would "not be considered eligible at this time" to be a substitute. The same was noted in his exit papers.

Two months later, he was filling shifts at Greco Middle School, where he continues to take short-term assignments.

District officials expressed surprise when shown Cyrus' and Spain's files. "That's something we are continuously working on, communicating with the different offices to make sure we have the proper alerts," Collins said.

Other files reviewed by the Times did not explicitly warn against rehiring, but pointed to problems nonetheless.

Jaclyn Honer had such a toxic relationship with her principal at Morgan Woods Elementary School that Honer's hair was falling out. By one account — which Honer denies — she said this about her boss: "F--- this b----. I hope she dies in her sleep tonight."

Tracy Roese said jokingly, in a class full of students at Freedom High School, that one might have a low math grade "because you're black." It's just her sense of humor, she told investigators. One freshman misunderstood, Roese said, and her enemies in the school blew the whole thing out of proportion.

Michele Simcox, a teacher at Knights Elementary in east Hillsborough, tested positive for alcohol use during a planning day in 2016. Simcox adamantly denied drinking and said it was a false positive, likely triggered by chewing gum. She was pressured to retire, she said.

All three have worked as Kelly substitutes.

Other teachers filled shifts after they resigned from the district over an ethical violation: They were accused of plagiarism in a course they needed to teach students with limited English skills. One of them, Sherena Murdock, is subbing at Young Middle School, though a spokeswoman for the Florida Department of Education said its case against her is still pending. Murdock, 28, resigned her district position in 2016 and is technically a Kelly employee, but she is listed on the science magnet school's website as a seventh- and eighth-grade science teacher. Reached by phone, Murdock declined to comment.

The substitute pool can be a way station for teachers who were let go after their first year or two of service under a process known as "non-renomination." Essentially, the principal does not believe the teacher is up to the job, and chooses not to renew his or her contract. Collins said her department encourages some of these teachers to work as substitutes.

"Nonrenewal is not necessarily an awful thing," she said. "They're maybe not ready to be a full-time teacher. But going out and substituting and looking at other models becomes effective as they're learning their craft."

Another common scenario involves teachers who were fired, or resigned to avoid being fired, because they did not meet all the requirements for permanent certification in the time limit given when they were hired, generally a year.

In some cases, teachers signed on with Kelly within days of their firing or resignation and wound up at the very same schools, filling their own vacancies — still technically unqualified, and earning a fraction of their former pay.

Eakins defended the practice, saying, "there are some people that are just natural-born teachers that have anxiety with tests." The teacher might be close to completing his or her certification. "It might be the math exam, good luck, that they're taking," he said.

As for keeping them in the same job, he said, "you almost have to look at things one by one to determine if it was the wise decision." It "may have been a very sound decision for kids because of the relationship, the expertise the person might have had in that area."

Collins agreed it is not a good idea to keep the teacher in the same job, at substitute pay, for a long stretch. Sometimes, the principal wants to keep the teacher, she said. She aims to get fully certified teachers into these jobs, and reviews long-term vacancies every month.

But the invoices show teachers with certification problems sometimes remain at their schools, as substitutes, for as long as four or five months.

Some are teaching the system's most vulnerable students — those in special education.

And some are filling vacancies in the highest-poverty "Elevate" schools. An analysis by the Times showed that F-rated Potter and Booker T. Washington elementary schools rank near the top according to how many days their students spent with substitute teachers.

By Kelly's calculation, 37 percent of the shifts in Hillsborough are used for unfilled teacher vacancies. About half that percent — 20 — are filled by teachers with full Florida certification. Weaver, however, pointed out that many of the other substitutes have college degrees and could be on their way to becoming certified.

The Times asked Eakins if it was reasonable for all parents to expect their children to have teachers with full credentials.

"That would always be my preference," he said. "Our ultimate goal is to have someone in that classroom who is fully certified, who is highly effective, who is meeting the needs of kids."

But there are simply not enough teachers coming out of the nation's colleges, he said. The district has to hire from other professions and hope the teachers complete certification requirements under the timetable prescribed by state law. Class size limits imposed years ago by the state also prove challenging, he said.

And life itself creates vacancies. "In my second year as a principal, I had 12 teachers who were expecting," Eakins said.

As for the high-poverty schools, Eakins said he continues to battle high teacher turnover as new principals seek to stabilize their staffs. In the meantime, he said, when the school uses a substitute, subject specialists and coaches from the district work alongside.

"That's how you balance the whole equity issue," he said.

• • •

Kenneth Spain, now 26, said he recognizes his error in talking about Jesus and pornography to his social studies students.

"Wrong place, wrong time," he said.

He was new to teaching and did not major in education in college. Returning to Tampa, he started out as a substitute. He coached football. A supervisor saw potential. His childhood assistant principal was the principal at Chamberlain, which had an opening in social studies.

"I thought, maybe this is meant to be," Spain said. "Maybe this is an act of God."

The job was like a honeymoon, he said. The end "was heartbreaking."

At Chamberlain, he said, "I loved teaching, loved being around students, inspiring them, empowering them and motivating them.

"I still see these students out in public now, and we talk, and they want me back in the classroom."

Other former teachers say they were pushed out unfairly, and there's no reason why they cannot return as substitutes.

Honer, 50, said she was targeted at Morgan Woods by a vindictive principal. Tactics included summoning Honer on Friday to a meeting on Monday so she would have to worry about it all weekend.

A transplant from New Jersey, Honer had not completed her Florida certification. But she was certain her principal was building a case against her anyway.

She said the principal of James Elementary School liked her and might have hired her, were it not for her missing math credential.

So she became a steady substitute at James. "I love what I do," she said.

Roese, who in 2014 made the "because you're black" joke, said the ninth-grader who complained was a homeroom student she rarely saw who took offense at an overheard comment. She told the racial joke to a group of biology students with whom she had built good rapport, she said.

Roese, 47, told investigators at the time that she had made such jokes before. When asked how often, she said: "Dozens of times. I say 'because I'm a blonde,' 'cause I'm a girl,' 'cause you're Mexican,' 'Puerto Rican.'?"

It's banter, she said, a way to keep the students interested, like when a visiting district science teacher told students, "you're all going to get to play with my balls."

Roese's situation was complicated by a break in her service over a certification issue, which would have enabled the district to push her out by not renewing her contract.

She insists the real problem was not the racial remark, which did not directly result in discipline. Rather, she said, she had made enemies by testifying against another teacher who slept with a student.

"This was whistleblower retaliation," Roese said.

"I should have run screaming and never set foot in the classroom again. But when teaching is in you, it's in you. You're going to come back in whatever shape, form, capacity is possible."

Contact Marlene Sokol at (813) 226-3356 or msokol@tampabay.com. Follow @marlenesokol