Two teenagers were arrested Monday for robbing the grave of an elderly woman and having sex with the corpse. The incident took place in Davao, Philippines, on Sept. 30.

The incident came to light after Isabel Bastatas’s family arrived at her grave on Sept. 30, a day after she was buried, and found something amiss. The family found that the tomb of the 84-year-old disturbed and the woman’s legs poking out of the coffin.

The family told police that they found the woman’s body without undergarments and her vagina was also visible. They felt there were signs of intercourse. Police then began investigating the alleged necrophilia at the cemetery.

A week later, police arrested the two teens in connection with the alleged necrophilia with the help of witnesses.

“The arrest was made after witnesses came to us to help with the investigations. They were pointing to one of the suspects, 'Erwin,' and another companion,” Lieutenant Colonel Ernesto Castillo said.

The suspects were held at the Department of Social Welfare Development Office as they were minors. Details including the age of the suspects were not released.

Meanwhile, police said they were trying to figure out what was stolen from the grave and how the woman’s body was interfered with. Investigation into the case was ongoing.

This image shows a pair of handcuffs at the Commissariat de Police Nationale (National Police Station) in Alfortville, France, Nov. 21, 2016. THOMAS SAMSON/AFP/Getty Images