China says the man who flew a small plane into Beijing’s tallest skyscraper was suffering from mental health problems and acted for personal reasons, according to authorities.

The pilot, identified only by his surname Liu, died in the crash at the CITIC Tower last week. Authorities said the investigation concluded the incident was “endangering public safety caused by personal reasons.”

A statement from the Chaoyang district government said Liu had chronic insomnia and anxiety. It also said his diary included “multiple expressions of ending his life,” and that he had a sport pilot’s licence granted in 2021 and a private pilot’s licence granted in 2024.

Officials said Liu, a 66-year-old Beijing resident, was a divorced freelancer who lived alone. They said he took off from Pinggu district for flights that included both solo and accompanying segments, and that during his solo flight he deviated from the designated area and lost contact with the airport before colliding with the high-rise building.

Thirteen people were injured in the crash, with officials saying at least one has been discharged from hospital.