MANILA, Philippines -- Ernest Albert Buan is still free to campaign for the post of mayor of Mandaluyong City, but he will have to do so from behind bars, according to the city election officer.

Mandaluyong election officer Romeo Alcazar said the 28-year-old Buan has not been disqualified from the mayoral race despite the drug charges against him.

?As far as his candidacy is concerned, there is no effect,? he told the Philippine Daily Inquirer.

?One of the grounds for disqualification is having a final judgment to the crime, and in his case, he is still under investigation.?

Alcazar cited the cases of Sen. Antonio Trillanes IV and former Zamboanga del Norte Rep. Romeo Jalosjos, who were able to campaign while under detention. Brig. Gen. Danny Lim, a candidate for a Senate seat, has remained in detention all these years for his role in alleged destabilization attempts against the Arroyo government, he noted.

Buan, who remains under police custody, will enter a plea of guilty or not guilty on drug charges on Feb. 15 before Judge Abraham Borreta of the Pasig Regional Trial Court Branch 154.

The arraignment of Buan in connection with the complaint for violations of Sections 5 and 11 of Republic Act 91655, or the Comprehensive Dangerous Drugs Act, against him has been scheduled for Monday at 8:30 a.m., court staff said.

Earlier, a prosecutor found cause to indict him on charges he tried to sell plastic sachets of a white crystalline substance, which later tested positive for cocaine, to undercover narcotics agents in a sting operation in a fast food restaurant in Pasig City on Jan. 29.

The camp of Buan, who is running under the Aksyon Demokratiko party against incumbent Mayor Benhur Abalos, has denied his involvement in the drug trade and suggested that the operation could just be a ?setup? by his political opponents.