A Muslim faith healer has been arrested for the brutal drugging and stabbing of 20 of his disciples at a Sufi shrine in Punjab, Pakistan.

The victims of the massacre were reportedly drugged with narcotic-laced food, stripped naked and then killed with a dagger and stick. Along with the 20 dead, four more people were wounded in the incident, which occurred around midnight between Saturday and Sunday. The four are in critical condition.

The alleged perpetrator of the crime is the 50-year-old shrine custodian and faith healer Abdul Waheed, who confessed that he killed these people because he feared that they had come to kill him, according to regional police chief Zulfiqar Hameed.

“The suspect appears to be paranoid and psychotic, or it could be related to rivalry for the control of shrine,” Hameed said.

Pervaiz Haider, a doctor in the hospital treating the survivors of the incident, said most of the dead were hit on the back of the neck. “There are bruises and wounds inflicted by a club and dagger on the bodies of victims,” he said.

Waheed was known for erratic behavior but was popular as a faith healer.

“Local people say Abdul used to beat the visitors who came to him for treatment of various physical or spiritual ailments,” local rescue service official Mazhar Shah said. “Sometimes he would remove the clothes of his visitors and burn them.”

According to Deputy Commissioner Liaqut Ali Chatha, people would come to the shrine for cleansing their sins and allow the caretakers to beat them with clubs. “But in this case the visitors were first drugged and then stabbed with daggers and hit with clubs, apparently during the cleansing process,” Chatha said.

The shrine was built two and a half years ago and named after the late boxer Mohammed Ali, a convert to Islam. It has become a popular place of pilgrimage and healing for Sufi Muslims.

Two other suspects were reportedly arrested together with Waheed.

Many hardline Muslims regard Sufis as heretics because of the mystical element of their tradition.

Earlier this year, militants of the Islamic State (ISIS/ISIL) carried out a massive suicide bombing on a prominent Sufi Muslim shrine in Pakistan, killing up to 88 people and wounding more than 300 others.

Last November, another Islamic State attack at a Sufi shrine in south-west Pakistan left a least 52 people dead and more than 100 others injured. A bomb blast hit worshipers participating in a ceremony at the shrine of the Sufi saint Shah Noorani, some 750 kilometers (460 miles) south of Quetta, the provincial capital of restive southern Balochistan province.

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