Updated

The Coast Guard says a Hawaii-based Coast Guardsman who disappeared more than three months ago was being investigated for illegal drug use at the time.

Coast Guard spokesman Chief Warrant Officer Gene Maestas told the Honolulu Star-Advertiser (http://is.gd/vTag5h ) that Petty Officer First Class Russell Matthews was being investigated for using marijuana. The offense could have resulted in the 15-year veteran being discharged from the Coast Guard.

Honolulu police say Matthews was incoherent when he returned to his home on Sunday night after a long absence and was taken to a hospital for observation.

The Coast Guard has said it doesn't know where Matthews has been or what he's been doing since his wife reported him missing on Oct. 9.