A semitrailer truck driver was watching a string of pornographic videos — more than a dozen in all — in the minutes leading up to him speeding through a construction zone and fatally striking a highway worker standing along a Twin Cities area interstate, according to charges.

Tate R. Doom, 47, of St. Paul Park, was charged Friday in Hennepin County District Court with criminal vehicular homicide and criminal vehicular operation in connection with the crash on Interstate 94 in Rogers last fall that killed Vernon C. Hedquist, 59, of Pillager, Minn.

Doom was booked into jail Friday night and remained in custody in lieu of $30,000 bail before an Aug. 12 hearing. Court records do not show him having secured legal counsel yet.

This case comes as Minnesota's law prohibiting motorists from holding their phones while driving takes effect on Aug. 1.

According to the criminal complaint:

The contracted road crew was working on the afternoon of Oct. 2 on the closed right lane of I-94 near County Road 81. Doom's semi rear-ended a pickup truck and trailer merging to the left.

The trailer separated from the pickup and struck Hedquist, while flying debris hit a co-worker. Both were standing on the shoulder as part of crew working on a drilling project in preparation for road work starting months later.

State Patrol investigators determined that Doom's semi was traveling 72 mph, slightly above the posted limit of 70 mph, and the pickup was going 50 mph.

Troopers seized two cellphones from Doom's semi for forensic examination, which show he deleted 14 video files from Pornhub.com.

Authorities recovered the files and show that he began playing them at 1:40:53 p.m.

His last of the 14 videos, which has a running time of 5 minutes and 14 seconds, started at 2:07:41 p.m., less than 90 seconds before Doom's semi struck the pickup and trailer.

"It appears, based on the investigation, that he was watching pornography at the time of [impact]," Chuck Laszewski, spokesman for the County Attorney's Office, said Monday.

Doom denied using his cellphone at the time of the collision and contended he was traveling at 50 mph.

Hedquist, a Sunday school teacher who was looking forward to deer hunting season and his 60th birthday the following month, had worked for WSB since 2014 and was a longtime Minnesota Department of Transportation employee before that.

"He absolutely was very concerned about his safety on the job," Hedquist's wife, Cindy, said a little more than 24 hours after losing her husband of 34 years.

Co-worker Thomas J. Wood, 64, of Maple Grove, was struck by vehicle debris and survived his injuries.

Doom was driving at the time for Vermeer of Minnesota in Burnsville, which sells heavy equipment for recycling and forestry needs.