A St. Landry Parish Sheriff’s deputy failed to engage the child safety locks in an inmate transport van, enabling inmate Matthew Q. Keyes to escape through the van’s back doors June 23, Sheriff Bobby Guidroz said Friday.

Guidroz announced Friday the findings of an internal investigation into Keyes’ escape.

While being transported from Opelousas to the Lafayette Parish Correctional Center, Keyes, 24, of Opelousas, somehow freed himself from his leg restraints and handcuffs, and jumped from the back door of the transport van while the vehicle was stopped at a red light in Lafayette, Guidroz said.

“We thought it sounded strange that an inmate secured in the back of a van with cuffs and restraints on would be able to escape,” Guidroz said.

Later, both Keyes and the transporting officer, deputy Earl Stevens, a corrections officer with more than 10 years of experience, took a voice-stress analysis test, similar to a lie detector, Guidroz said.

The inmate told investigators that Stevens assisted him in his escape, but the test revealed “that the deputy did not assist, and that the inmate was telling a lie,” Guidroz said.

“How he got out of the restraints remains a mystery to us,” Guidroz said.

Keyes, who had been sentenced earlier that day to more than 20 years in prison, remained on the loose for about a day before he was captured following a high-speed police chase into Rapides Parish.

The investigation did fault Stevens for failing to follow a departmental policy that requires deputies to engage the child safety locks within the vans, Guidroz said.

“If (the locks) would have been engaged, Keyes would not have been able to get out of the van,” Guidroz said.

Stevens will be disciplined for his actions, Guidroz said, adding the discipline could range from a letter of reprimand to termination, depending on the deputy’s previous performance history.

Stevens was placed on administrative leave pending the investigation and has since returned to work, although he has not yet been disciplined, Guidroz said.

“I’m disappointed that this has happened,” Guidroz said. “Thank God the inmate was captured.”

Keyes was sentenced to more than 20 years in prison on charges of unauthorized use of a motor vehicle, possession of marijuana with intent to distribute, home invasion and two counts of burglary of a dwelling.

He also faces separate charges in Lafayette Parish, and will likely face additional charges in St. Landry and Evangeline parishes due to his escape.

During the escape, Keyes allegedly stole a vehicle and led authorities on a 30-mile police chase at speeds of more than 130 mph before he surrendered in Rapides Parish.