At least 20 people were killed and four others were injured by the custodian of a shrine in Pakistan’s Punjab province on Saturday night. Abdul Waheed had called the devotees to his room individually and drugged and stripped them before beating them to death with a machete and dagger, said Deputy Commissioner of Sargodha Liaquat Ali Chatta, quoting a survivor, Dawn reported.

The motive behind the murders has not been ascertained yet, but Chatta has alleged that Waheed was mentally unstable. Residents of the locality, however, have denied the claim.

Police reached the shrine of Ali Ahmed Gujjar in Sargodha after one of the survivors reported the incident at the District Hospital, the deputy commissioner said. They arrested Waheed and his four close associates. They have been moved to an undisclosed location, according to Daily Pakistan.

Waheed, a resident of Lahore, is believed to be an employee of the Election Commission of Pakistan in Sargodha. Local residents said he visited the shrine twice a month and tortured devotees by setting them on fire, claiming that was a healing process.