MONTREAL—Driving home from his first day of testimony in front of Quebec’s anti-corruption inquiry, Gerald Tremblay felt something was wrong. The former mayor found all of the lug nuts on one wheel unscrewed.

Montreal daily newspaper La Presse is reporting that Tremblay is now under police protection, as the Surete du Quebec investigates if the former mayor was being targeted as a witness at the Charbonneau Commission.

The investigation, underway since the incident last Thursday, has been discrete with no public mentions until the newspaper’s report on Tuesday morning.

After driving himself to his first hearing, Tremblay was transported to his final day of testimony on Monday in a police vehicle.

The former mayor wasn’t the first witness to be provided with police protection. After a number of bombshell revelations in 2012, former construction owner Lino Zambito was placed under the watch of the SQ’s witness protection unit.

The Montreal police and SQ are unwilling to comment on the investigation.