The driver of a tour bus that fatally struck an Alaskan town’s mayor and her mother last week in Washington was using a handheld cellphone at the time, according to court documents filed Thursday.

Police called the distraction — recorded on surveillance video from inside the bus — “a gross deviation” from reasonable driving that “created an extreme risk of death or serious bodily injury.”

The driver of the bus was identified as Gerard Derrick James, 45, of Baltimore. He was arrested Thursday and charged with two counts of involuntary manslaughter.

The Dec. 19 crash killed Monica Adams Carlson, 61, and her mother, Cora Louise Adams, 85, who were walking north on Seventh Street NW when they were struck as they crossed Pennsylvania Avenue, near the National Archives and Navy Memorial.

When Monica Carlson’s ­brother-in-law, Steven Hites, learned of James’s arrest, he said: “We feel very sorry for everybody involved. It’s a tragedy all around.” After learning later that the driver had apparently been on a cellphone, he said, “God almighty, that says it all.”

Carlson and Adams had traveled to Washington to visit the White House and see Christmas decorations, which they did hours before they were struck. They also visited Arlington National Cemetery to honor their son and grandson, a Marine who served in Afghanistan.

Police have said Carlson, the mayor of Skagway, Alaska, and Adams, who lived in Elbe, Wash., and ran a hamburger stand for tourists and hikers at Mount Rainier, were in a crosswalk with the walk signal as the bus turned left off Seventh onto westbound Pennsylvania. The incident occurred about 9:40 p.m. The women were declared dead one minute apart at different hospitals — Adams at 10:16 p.m., her daughter at 10:17 p.m.

Authorities said lighting was good at the intersection and the bus was in proper working order, with headlights on. They also said James passed a drug and alcohol screening. He had a valid commercial driver’s license and no history of traffic infractions. The bus had no passengers at the time.

James told police he did not see Carlson and Adams, and stopped after he heard the impact. The bus at that point had traveled 183 feet from the intersection. Police said one of the women was caught under the bus and dragged. The arrest affidavit filed in D.C. Superior Court indicates that an attorney for the bus company turned over surveillance video from cameras inside the bus that showed the incident from two angles.

One camera shows James talking on the phone as he is driving, according to the affidavit. He put the phone down with his left hand as he entered the intersection, police said in the document. But the phone rang a moment later, and the affidavit says James picked it up with his left hand and switched to his right as he started to turn onto Pennsylvania.

Police said the crash can be heard on the surveillance video.

Representatives for the bus operator, Maryland-based Eyre Bus, Tour & Travel, did not respond to interview requests Thursday. Melanie Hinton, a spokeswoman for the American Bus Association who last week spoke on behalf of the bus company, declined to comment and referred questions to James’s attorney. No one answered the telephone at James’s home.

A Superior Court judge on Thursday ordered James released until a Feb. 15 preliminary hearing. His attorney, Todd S. Baldwin, in an interview called the case “a tragic, terrible accident.”

He said his client “is doing all he can do to cooperate with the investigation. Let the criminal-justice system run its course.”

Baldwin declined to comment on specifics of the case, including the assertion from police that James was distracted by his phone.

The incident had similarities to a fatal crash at the same intersection on Valentine’s Day 2007. That incident prompted officials to adjust a traffic signal to give pedestrians an early start for crossing.

Martha S. Schoenborn, 59, and co-worker Sally Dean McGhee, 54, both of Alexandria, were leaving work at the Federal Trade Commission and were heading north in the crosswalk with a walk signal when they were struck by a Metrobus turning left onto Pennsylvania.

The Metrobus driver pleaded guilty to two counts of negligent homicide and was sentenced to six months in jail and three years of supervised release, court records show. Metro agreed to pay $2.3 million to settle a lawsuit filed by one of the victims’ husbands.

The deaths of Carlson and Adams brought the number of traffic-related fatalities in the District this year to 35 — including 14 pedestrian deaths — up from 30 in 2017. This year’s tally is the highest since 2008, when 39 people died in traffic-related incidents.