ANCHORAGE — A pilot who crashed a small Civil Air Patrol plane into office buildings in downtown Anchorage, Alaska, was using the search-and-rescue aircraft without permission, the organization said Monday.

Civil Air Patrol national spokeswoman Julie DeBardelaben said pilot Doug Demarest did not make a request to fly, as required.

Demarest was the only person killed on Dec. 29 when the Cessna 172 clipped several buildings, including one housing the law firm where his wife works, before most area businesses had opened for the day. There were no injuries on the ground.

Family spokeswoman Jahna Lindemuth has said the death was a suicide. Lindemuth, a managing partner at the law firm, Dorsey & Whitney, has declined to say how the family knew it was suicide and she asked that their privacy be respected.

The FBI is leading the investigation and has released little information.

The 42-year-old Demarest , who joined the Civil Air Patrol in 2010, crashed the plane after taking it from a hangar at Merrill Field on the edge of downtown.

“The pilot involved in the AK incident did not obtain a flight authorization,” DeBardelaben said in an email to The Associated Press.

The organization is a civilian auxiliary of the U.S. Air Force that helps with search and rescue, disaster relief and homeland security across the nation.

Merrill Field’s tower is staffed between 7 a.m. and 10 a.m. during the winter, airfield manager Paul Bowers said. The crash occurred at 6:18 a.m., but Bowers said no one at the airfield was aware of the plane taking off. Towers at many smaller airports in the nation are similarly staffed.

Bowers has said Civil Air Patrol officials were alerted after maintenance crews found the hangar door open.

There was no sign of forced entry.

Dorsey & Whitney reopened its offices on Monday, almost a week after the crash. Demarest’s wife, Katherine Demarest, was recently named a partner at the firm.