ANCHORAGE — The Coast Guard civilian charged with killing two co-workers at a Kodiak communications station told an FBI agent he was late getting to work the day of the deaths because he returned home to change a soft tire, but he had no explanation for why the trip of a few miles should have taken more than 34 minutes.

James Wells, 62, is charged in federal court with two counts of first-degree murder in the deaths of Richard Belisle, 51, and Petty Officer First Class James Hopkins, 41, shortly after they arrived for work around 7 a.m. April 12, 2012.

Wells was also due to work at that hour. In interviews over two days with FBI agent Kirk Overlander starting the night of the shootings, Wells said he started into work, detected a soft tire, stopped at a hotel near the entrance to the Kodiak Airport, checked the tire and returned home to change it.

Unbeknownst to Wells, a security camera at the gate of the nearby Coast Guard main gate recorded his truck heading for the communication station by 6:48 a.m. and heading in the opposite direction toward his home at 7:22 a.m., a gap of 34 minutes.

A day after the shootings, Overlander told Wells he drove the route and made it in less than 10 minutes.

“We’re running into some issues here,” he said. “There’s a 34-minute window of time.”

Asked if he could account for the time difference, Wells could not offer a theory.

“What are you implying?” Wells asked.

“We’re baffled,” Overlander said.

“So am I,” Wells said.

Prosecutors say Wells used the time to switch to his wife’s car parked at the airport, follow Hopkins to the communication station and shoot Hopkins and Belisle. They contend he was in and out of the Rigger Shop, where communication antennas were built and repaired, in five minutes, giving him time to drive back to the airport, switch back to his pickup and drive home, where at 7:30 a.m. he called Hopkins’ office phone to report he would be late because of the flat tire.

The motive, said assistant U.S. Attorney Bryan Schroder, was the Coast Guard exerting more control over the nationally recognized antenna expert and seeing Belisle and Hopkins making him increasingly irrelevant.

Federal public defender Rich Curtner in his opening statement said Wells suffered from chronic diarrhea following gall bladder surgery and was delayed returning home the morning of the murders because he spent 20 minutes in a bathroom of a commuter airline.

Wells made no mention of using an airport bathroom to the FBI and told Overlander he checked his tire at a hotel near the airport entrance.

“I probably turned around at the Comfort Inn,” he said.

Sometime after acknowledging he had no explanation for the rest of the 34-minute period, Wells exercised his right to have an attorney and the interview ended.

Prosecutors ended their case with testimony from Belisle’s 18-year-old daughter, Hannah, who was 16 at the time of the murders. Hannah Belisle acknowledged she had used cocaine and other drugs, once ran away from home and dated a 22-year-old known drug user before her father’s murder. But she said that no one she knew had reason to harm him.

Defense attorneys have suggested the FBI immediately zeroed in on Wells and ignored other suspects, such as associates of Hannah Belisle.

Defense attorneys will call their first witnesses Thursday.