FORT WORTH — Throwing gang signs could result in authorities throwing the book at you.

An 18-year-old Fort Worth man found himself in a world of trouble Wednesday night when he flashed gang signs at a passing car, only to find that its occupants were undercover gang officers.

The incident occurred about 10 p.m. as the two officers, in an unmarked car, passed a home in the 3800 block of North Terry Street — a known hangout of a north side gang.

The officers called for officers in marked units to detain the teen for disorderly conduct/gesture, said Lt. Dean Sullivan, a police spokesman.

But that wasn’t the teen’s only mistake, police said.

As officers patted the teen down, they found a bottle of what appeared to be Xanax inside his pocket. The teen could not explain why he had the pills, Sullivan said.

Then, when officers asked for his identification, the teen told them it was in his bedroom and led them into the home. There, on a table, officers spotted a clear plastic baggie with what they believed was cocaine inside, Sullivan said.

Based on the discovery, narcotics officers were called and obtained a search warrant for the home. They uncovered a cache of weapons, including an Uzi, an AR-15, a .44-caliber Magnum pistol, a 12-gauge shotgun and other handguns. Officers also found approximately 3.6 kilos of suspected cocaine, a pound of what appeared to be marijuana and about $65,000 in cash, Sullivan said.

“In addition to that, there were six wrappings from kilos of cocaine that they had already apparently opened and sold, we presume, or distributed,” Lt. Robert Rangel said.

The 18-year-old, identified as Alex R. Perez Jr., and his 17-year-old brother, Paul A. Perez, were arrested on suspicion of drug and weapons violations.

Agents from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives and Immigration and Customs Enforcement are assisting in the investigation.

Authorities will seek federal charges against the 18-year-old and state charges against his brother.

“It was a bad career move and lousy timing for the gang member,” Rangel said.