SUGAR LAND, Texas -- Matthew Ross McCombs and Sean Huston Brown, both 18, were apprehended Wednesday afternoon while trying to cross the U.S.-Canadian border in Ontario, KPRC Local 2 reported.

The suspects were being transported to Port Huron, Mich.

Arrest warrants were issued Wednesday for the two teenage friends of a slain 16-year-old girl, Ashton Glover. They were the last ones to see the girl alive, officials told KPRC Local 2.

Glover, 16, was last seen early Saturday at the It's A Grind coffee shop on Sweetwater Boulevard in Sugar Land. She was found dead by a construction crew laying utility lines off of Oil Field Road and Thompson's Ferry Road just before noon Monday.

McCombs and Brown were both charged with murder on Wednesday.

"We do not have a motive," Fort Bend County Sheriff Milton Wright said. "These two individuals were apparently friends with (Glover) for quite a while. They did go to school together."

Officials said McCombs and Brown live next door to each other. They were last seen Monday afternoon in a black 1999 Dodge Ram pickup truck with Texas license plate 2DD XO8.

Investigators went to the suspects' homes to search for evidence earlier on Wednesday. They said at least a dozen bags and boxes containing clothing, computers, shovels and other items were removed from the garages and houses.

Wright said the pair apparently lied when they told investigators they saw Glover get into a white pickup truck after meeting her at a coffee shop.

"We don't believe there was a white Toyota pickup truck involved in this in any manner," he said.

Authorities said Glover's truck was recovered Monday evening, about five miles from where her body was found.

Surveillance video showed someone getting into her truck and driving off, but the quality of the video was poor and was difficult to determine the driver's gender, according to authorities.

An autopsy was conducted to determine Glover's cause of death. The report said she was not sexually assaulted.

"There's blunt force trauma to the head. We now believe that the broken arm was possibly caused by the pickup," Wright said.

Glover's mother wants justice.

"I've had nightmares just wondering if I could have been there to protect her. But, you know, I couldn't. I did all I could do, and I will do all I can do to make sure these boys pay," Sue Smith said.

Smith said she did not recognize McCombs and Browns as friends of her daughter.

Funeral Arrangements Finalized

Funeral arrangements for Glover were finalized Wednesday.

A visitation will be held Friday beginning at 5 p.m. at the Settegast-Kopf funeral home on the Southwest Freeway near Williams Trace Boulevard.

The funeral services will be held Saturday at 10 a.m. at the First Colony Church of Christ in Sugar Land.

Glover will be laid to rest in Kennard, about three hours north of Houston.