ABUJA, Nigeria (AP) — A nurse was identified on Friday as the “principal suspect” in the mysterious death of a Nigerian Afrobeat star, which triggered dayslong protests by thousands demanding justice.

Investigations into the death of Ilerioluwa Aloba, better known as MohBad, in the commercial hub of Lagos have pointed to the nurse who treated the late singer before his death, Lagos police chief Idowu Owohunwa told reporters on Friday.

The nurse was invited to treat Aloba for an unknown illness at his Lagos residence where she “administered three different injections which are believed to have occasioned the chain of reactions that directly resulted in the death of the singer,” Owohunwa said.

The nurse is in custody, but there has been no arraignment and no formal charges have been brought.

The police statement came after a closely-watched investigation that prompted Aloba’s body to be exhumed for an autopsy as authorities searched for answers to what killed the 27-year-old on Sept. 12.

Widely known as one of Nigeria’s fastest-rising young pop stars, Aloba was confirmed dead at a Lagos hospital in unclear circumstances. Questions about the cause of his death prompted protests, rallies and grief spilling onto the streets across the West African nation.

His death also drew many to his songs, where he mostly spoke about life growing up and his quest for a better life.

The outrage over the singer’s death was also directed at Naira Marley, his former boss and controversial musician currently on trial in Nigeria for alleged internet fraud.

Marley was accused of maltreating Aloba, which he denied. He remains in police custody as one of the suspects in the case, the police said.

The police said that its investigation found that doses of some drugs administered to Aloba by the nurse “immediately and directly triggered the reactions (including vomiting, goose bumps, convulsion) that eventually resulted in the singer’s death.”

The suspect is an assistant nurse who wasn’t qualified to administer the medications, Lagos police chief Owohunwa said.

“She acknowledged that it was the injections that she administered on the deceased that triggered the reactions which eventually led to Mohbad’s death.”