AUGUSTA – An 18-year-old man was arrested Thursday on an elevated aggravated assault charge stemming from an attack two days earlier that critically injured a former state legislator from Pittston and his 10-year-old daughter.

Prosecutors are seeking $1 million bail for Leo Hylton of Augusta, who was being held at the Kennebec County Jail in Augusta and is scheduled for an initial court appearance Friday, Sheriff Randall Liberty said.

Hylton is charged in the pre-dawn attack Tuesday at the home of William Guerrette Jr., 48, who served in the Maine House of Representatives in 1995-96, and his daughter Nicole.

Hylton offered no resistance when he was arrested at the downtown apartment he shared with a 20-year-old man who has charges pending in connection with a theft at Guerrette’s home last November.

Details of the Guerrettes’ injuries and where they are hospitalized have not been released, but police said both father and daughter remained in critical condition Thursday. Guerrette’s wife and a teenage son and daughter were also home but were not hurt.

“This is one of the most violent crimes I’ve seen,” said Liberty, “especially as it involved a young child.” The investigation has been given top priority with 14 state and county investigators working around the clock, he said. Others may be charged, he added.

Hylton’s roommate, Daniel Fortune, was one of two men charged in connection with a theft at the Guerrette home last November while Guerrette was away on vacation.

Fortune has pleaded not guilty to the theft of Guerrette’s safe containing $30,000 in cash, rare coins and historic bank notes valued at more than $175,000. The other man, William Darrell Page Jr., 19, of Manchester, is serving his sentence after pleading guilty.

Liberty declined to comment on what motivated the attacks. Asked if he thought Fortune was involved in the newer case, Liberty said, “I’m not aware that he was.”

Fortune has been questioned but has not been charged in the attack. Instead, he was arrested on an unrelated warrant and held at the county jail.

Investigators are still searching for evidence in the home-invasion case, and believe some of it may have been discarded in the Pittston and Whitefield area.

“We ask that anyone who has trash placed out for collection by the road to check their trash to see if anything suspicious is located there,” said Liberty.

“I’d like to emphasize that based on all the evidence that we’ve collected so far, the residents of Pittston are safe, as are the communities that surround Pittston,” Liberty said.

He asked that anyone with additional details call the sheriff’s office or state police.