CASCO — The man who was behind the wheel in a car crash that killed a 4-year-old boy last month in Casco has been reported missing.

The Cumberland County Sheriff’s Office said Michael Minson, 28, of Casco has not been seen since Sept. 9 and was reported missing by his mother Thursday.

Minson was at the wheel of a 1993 Honda Civic on Aug. 11 when it went off rural Route 11 just before 6 a.m., hitting a utility pole and splitting the car in two. Cameron Petersen was killed and his mother, 26-year-old Crystal Petersen of Gray, was critically injured.

“The reality is we don’t know where he’s gone,” Sheriff Kevin Joyce said during a news conference Monday. “It’s my understanding that on a couple occasions he’s done this in the past, so we don’t know if it’s suspicious. We don’t know if it’s taking off with some friends or fleeing the state. We just don’t know.”

Authorities are now looking to see if Minson left any paper or online trail to indicate his whereabouts in the eight days between Sept. 9 and this past Thursday, Joyce said.

He said investigators haven’t ruled out that Minson may have harmed himself or been harmed by someone else.

“We’re tracking this as a missing person somewhere out there, and we’re looking at it from that angle,” he said.

Minson did not have a valid license at the time of the crash and police said he appears to have been speeding. He has not been charged, although Joyce said his office has largely concluded its investigation and forwarded evidence to the Cumberland County District Attorney’s Office to decide whether to charge Minson.

Crystal Petersen’s condition has improved, but she faces a lengthy recovery and will likely never be the same, her mother, Teresa Petersen, said in an interview Monday.

Petersen said her daughter spent roughly a month in the intensive care unit and has undergone four operations – including brain surgery and reconstruction surgery – for injuries to all four lobes of her brain. She is awake, talking and recently began walking, but she suffered a traumatic brain injury that has severely affected her physically and intellectually, Teresa Petersen said. She expects her daughter to require 24-hour care after she is released from the hospital, at least initially.

Teresa Petersen believes that Minson is not missing and is hiding, and she and her family hope that police will complete the investigation and arrest him on charges.

“He didn’t only take Cameron from us that day; he took Crystal from us, too,” Teresa Petersen said. “She is not the same person.”

Petersen said Cameron’s 9-year-old brother is “devastated” by the loss of his sibling and by his mother’s severe injuries.

Minson and Crystal Petersen had just started dating and he was apparently rushing to get to his job at Dunkin’ Donuts on Route 302 in Naples on the morning of the crash.

The Cumberland County Sheriff’s Office said Minson had been despondent since the crash. He was last seen by his mother on Sept. 9 when he left with some friends for the night, the sheriff’s office said.

The sheriff’s office asks that anyone with information about Minson’s location contact Detective Brian Ackerman at 774-1444, ext. 2215.

Staff Writers Scott Dolan and Kevin Miller contributed to this report.