Police found Stuart's 5-year-old and 2-year-old sons badly bruised, malnourished and dehydrated on Wednesday after the woman's landlord called police to check on the welfare of the kids.
The younger boy had severe bruising to his forehead and cheek, and his lips were so dry they had cracked and bled, said Cpl. Anthony Bertagna, the Santa Ana police spokesman. The 5-year-old had swollen arms and was extremely dehydrated, and both boys had bruises and knots on their heads, Bertagna said.
Bertagna said Stuart, who was arrested Wednesday, admitted hitting her sons but didn't think she was striking them too hard. She also confessed to chaining the boys to their bed and crib by their ankles and refusing to feed them or give them water.
"She tied the kids to their beds using bandages, shoelaces or chains to keep them from taking off while she slept," Bertagna said. "She didn't feed the boys, especially the 2-year-old, because she was potty-training him" and was tired of changing his soiled sheets.
Paramedics took the boys to a hospital to be treated for dehydration, malnutrition and injuries. They remained hospitalized Friday, but expected to recover.
Authorities said Colin was arrested at 2:20 a.m. Friday after police reviewed the evidence in the case. He is not the father of the two boys and is married with two children of his own.
Stuart told police she met Colin in February and he gave her advice on how to discipline her children, which is when police suspect the worst of the abuse began.
"She started dating this guy February 20th, she remembered the exact date, it was the date he asked her to be his girlfriend and then that's when the abuse started," said Bertagna.
Santa Ana police detectives said Colin instructed Stuart to tie up the boys and withhold food and water to keep them from bedwetting.
"That somebody would starve a child, would abuse a child and not give a child water, as well as the fact that this individual that we arrested was somebody that works with elementary kids schools, behavioral issues, that's what's disturbing," said Bertagna.
Authorities say Colin has been employed as a behavioral technician at Durfee Elementary School in the El Rancho School District in Pico Rivera for the past four months. He is also a student at Cal State Fullerton, working on getting his Master's degree in teaching.
Authorities are now investigating whether Colin has abused any of the children at the school and whether he has abused his own children, a 4-year-old boy and a baby girl.
"I am just so sick, I think that is so awful. Awful, awful, awful. I can't believe a mother could do that," said Julie Plamondon, who lives in the condo complex where Colin lives with his family.
Many neighbors were shocked by his arrest, but said they never saw him with his kids.
"I don't see them often but when I do they're with the wife. She's pushing one in a stroller and the other one's walking behind," added Plamondon.
Police said Colin's wife only learned he was having an affair with Stuart on Friday when she spoke with detectives.
If convicted, Stuart and Colin could each face more than seven years in prison.
The Associated Press contributed to this report.