EL PASO, Texas (Border Report) – The Tamaulipas Attorney General’s Office is confirming a community group’s claim that it found multiple human remains near the border city of Matamoros.

Colectivo Amor por los Desaparecidos (For the Love of the Disappeared Collective) notified authorities regarding its findings on Monday and Tuesday.

“Stemming from searches by the collective, state authorities took note of bone fragments exposed to heat in two sites, one near kilometer 85 of the Reynosa-Matamoros highway, the other in Sierrita farm (west) of Matamoros,” the Attorney General’s Office said in a statement.

The state’s medical examiner picked up four sets of bones and 54 bone fragments from the first site. Seven steel drums were found at the second site; prosecutors confirmed bone fragments were found in at least one of the drums.

Reynosa, Matamoros and even Laredo to the west for the past few years have been teeming with violent cartel activity. Community groups calling themselves collectives have been searching for missing relatives for just as long.

What authorities mean by “exposed to heat” is that human bodies were burned to the bone, the community activists say. That’s a common practice for cartels trying to hide the bodies of victims after murdering them; the out-of-the-way places this activity occurs are colloquially known as “kitchens.”

“We are at the extermination-by-fire-exposure site,” Martha Quintana, a member of the collective, said during a Facebook Live broadcast on Tuesday. “We are going to show some pieces of clothing found at the site to see if anyone can identify them.”

The broadcast shows discarded metal drums in the brush near an abandoned house. Searchers wearing surgical gloves pick up torn jeans, shirts and jackets. Some items appear to be bloodstained. They go from size small to extra-large. A woman’s blouse was found as well.

“Those were used to blindfold them,” Quintana said of soiled long strips of cloth found near bone fragments.

For the Love of the Disappeared Collective last year helped Mexican authorities locate 27 bodies in nearby Reynosa. Most of the bodies had been hacked to pieces.

The Attorney General’s Office said it would conduct DNA testing on the bones. It’s a complicated and lengthy process, it said in its statement.

“This office reaffirms its commitment to work with the families in searching and locating the missing persons,” the statement said.