Four people were in custody yesterday facing possible federal weapons charges after Ho-nolulu police found a hand grenade in a pickup truck during a drug bust.

Police said an undercover officer made a drug buy at 12:50 a.m. on Kuhio Avenue near Walina Street from a man and a woman standing next to a pickup truck. The group was arrested in Waikiki yesterday morning on suspicion of drug offenses.

Officers noticed a packet of methamphetamine in the lap of one of two men seated in the truck. When one of the men was removed from the truck, officers saw more packets of drugs and the hand grenade, police said.

Bureau of Alcohol Tobacco Firearms and Explosives resident agent in charge Tracy Elder said an initial X-ray revealed a fuse, but that the grenade must be taken apart to determine if it is live or a practice ordnance. Usually, when an explosive ordnance is discovered, the Army or the ATF blows it up in a safe area.

Reach David Waite at dwaite@honoluluadvertiser.com and Peter Boylan at pboylan@honoluluadvertiser.com.