A Pennsylvania man was arrested Monday after allegedly setting fire to his ex-girlfriend’s home and killing her three sons.  

Preston Daquen Bonnett, 26, faces two counts of criminal homicide and three counts of arson for the Oct. 25 fire which killed Erik Dupree, 16, Devon Major, 12, and Ezekiel Major, 7, reported Citizen’s Voice.

The older boys died of smoke inhalation and Ezekiel Major was flown to Children’s Hospital of Philadelphia, where he died Saturday.

“The investigative team worked three days straight without any sleep,” District Attorney Stefanie Salavantis said during a press conference Monday evening. “They are showing amazing strength in such a trying time. It’s unbelievable how strong they are being.”

According to a police affidavit filed in court, the children’s mother, Susan Major, was at a work event on the night of the fire. Her three children were home alone and Major told police she had security cameras hidden in her home.  

Bonnett and Major, 48, met on Craigslist in 2015 and were involved in fraud charges months later after the two allegedly used fraudulent debit cards to buy gift cards and other items.

They eventually pleaded guilty to a misdemeanor theft charge and got a year of probation.

However, this summer, the couple had a giant falling out when Major let Tyla Marie Griffin, 28, stay at her home. One evening, Griffin brought Bonnett to Major’s home without permission and Major kicked them both out of the house. She then found a device used to make fraudulent credit cards in Bonnett’s belongings and called the police. Bonnett and Griffin face 25 charges, including felony counts of access device fraud and conspiracy.

Major also told police that Bonnett, who was not immediately arrested, was angry with her and had returned several times in an effort to retrieve his belongings, according to the affidavit.

During questioning, Bonnett denied having problems with Major and said he was not at her home, yet security footage from Major’s home showed Bonnett walking around the porch just minutes before 911 was called to report the fire.  

Police arrested Bonnett and Griffin the day after the fire on charges related to the credit-card fraud case and they are being held at the Luzerne County Correctional Facility.

Bonnett’s bail had been set at $150,000 in the fraud case, but the new charges mean he will not be eligible for bail.