PORT-AU-PRINCE, Haiti (AP) — Supporters of former President Jean-Bertrand Aristide clashed with UN peacekeepers Thursday as the popular former leader faced possible arrest for not providing court-ordered testimony in a criminal investigation.

About 150 Haitians had erected barricades of stones and burning tires outside Aristide’s home in Port-au-Prince to prevent any attempt to arrest him, keeping traffic at bay along the busy street largely without incident much of the day.

But some demonstrators pelted an SUV carrying U.N. personnel with stones, forcing the occupants to flee into a nearby home. They were subsequently rescued by peacekeeping troops, who then cleared the protesters and their barricades using tear gas and armoured vehicles.

The source of the tension was a summons issued by investigating magistrate Lamarre Belizaire for testimony from Aristide, whose ouster in February 2004 amid a violent rebellion triggered the deployment of a UN peacekeeping force that has been in the country ever since.

Belizaire issued the summons ordering Aristide to appear in court Wednesday. A copy of the order obtained by The Associated Press says the case involves allegations of laundering drug money but does not provide details.

Aristide lawyer Mario Joseph said the former president never received the summons at his home, where he has largely lived a secluded life behind high walls since he returned in March 2011 from exile in South Africa. The lawyer showed up at the court at the appointed time after hearing media reports about the hearing and brought a letter explaining why the summons should not be considered properly served.

The judge himself did not show up at the hearing and he could not be reached for comment. Under Haitian law, the judge could issue an order requiring police to take Aristide into custody for questioning, but it was not known whether he did so.

Joseph said he had been unable to reach the judge to clarify the situation. The lawyer said the summons was not properly served on the former president and thus he could not be legally taken into custody as a result.

Aristide remains a polarizing figure in Haiti. He is popular among a large segment of the population and his supporters allege that the criminal investigation is part of a campaign to keep the party that he founded, Fanmi Lavalas, from trying to build support ahead of legislative elections expected by the end of the year.

“The judge is a political judge,” Joseph said. “He is an opponent of Fanmi Lavalas. All this is an act to block Fanmi Lavalas from taking part in the election.”