MCALLEN – Investigators are breathing a sigh of relief after busting a group making and delivering hand grenades. Those grenades were being manufactured by a teenager.

A tip from an informant sparked the interest of the Bureau of Alcohol, Tobacco, Firearms and Explosives. The grenades had the potential to kill dozens. They were for sale to anyone with the money.

No one would have suspected what was being made in a shed in San Juan, homemade grenades. Law enforcement agents with ATF were immediately concerned.

Special agent Robert Flores explains their concern due to "the danger of not only hurting themselves, but others because of the potential for a large scale destruction."

The craftsmanship was sophisticated, said Flores, "Well, the person kind of knew what they were doing."

Behind it all were several men.

Nineteen year-old Noe Gonzalez was buying materials online and from local stores and making the grenades.

Jonathan Sanchez-Torres, 20, delivered the homemade devices to four other men, Anthony Ozuna, 20, Alfredo Rivera, 24, and Pedro Vega-Genova, 40.

Those men sold at least 50 grenades to an unknown group. ATF investigators believe those devices were exported to Mexico.

Robert Vela had experience in the berets. He has used these type of grenades modeled after the military's M67s.

Vela said, "I wouldn't want to be living next door to that, because it just takes any little accident for the actual detonation powder to go off with any spark, heat, humidity, whatever it takes. It can just like mess up the grenade. Malfunction in front of you."

He tells CHANNEL 5 NEWS, M67s have a kill radius of five-meters and it can seriously injure someone within a 15 meter radius.

Court documents show the grenades ATF purchased during their undercover operations were broken and tested.

Inside they found powder that could ignite and steel ball bearings that could steal a life away.

ATF agents got the tip about these weapons in the Rio Grande Valley on November 3, 2016. They made contact with the group just two days later.

Agents bought all their grenades available taking them off the streets in four separate undercover operations. That wasn't enough. They wanted the source.

Flores said for the case, "It was big for the fact that we not only arrested everyone involved, but we got everyone who was fabricating it."

Gonzalez and the other five are all serving sentences in federal prison.

ATF tells us this isn't their first grenade investigation. They hope they never see one working at this scale again.

The six men are serving sentences ranging from 8 to 20 years in federal prison.

Gonzalez is serving over 16 years in federal prison. Vega-Genova received a 20 year sentence; Montoya-Rodriguez, Rivera and Sanchez-Torres will serve 10 years and Ozuna will serve over 8 years.

Agents ask the public to report suspicious activity to police or federal agents.