DENVER (AP) — A former soldier accused of killing a transit guard in Denver last month says he supports the Islamic State group.

But investigators say they have no evidence the group had anything to do with the killing.

Joshua Cummings in a telephone interview from jail told The Associated Press he pledged allegiance to the group after fasting three days in the jail.

He says he did so to purge the oath he took to uphold the U.S. Constitution when he joined the Army in 1996.

The 37-year-old Islamic convert from Pampa, Texas, declined to say whether his Islamic State support led him to allegedly shoot Scott Von Lanken in the head on Jan. 31.

Denver Police Commander Barb Archer says detectives do not have a motive for Von Lanken’s killing.