SAN DIEGO - Authorities blocked off traffic lanes around a Skyline-area police substation Tuesday and called in a bomb squad after a citizen dropped off what turned out to be a dummy hand grenade.

The man walked into the SDPD Southeastern Division precinct house in the 7200 block of Skyline Drive and showed officers the device about 12:45 p.m., saying he wanted to dispose of it, Lt. Andra Brown said.

As a precaution, the object was taken outside into a parking area, which officers then closed off to the public along with a stretch of nearby street.

The San Diego Metro Arson Strike Team was called in to investigate. The squad quickly determined that the device contained no explosive material and took custody of it.

The man who dropped off the mock grenade told authorities it had been a keepsake of his recently deceased father's, said Maurice Luque, a spokesman for the San Diego Fire-Rescue Department.