Toronto police and transit officials are holding a news conference to renew their appeal for tips as investigators hunt for a person who shot a TTC fare collector a year ago Tuesday.

The TTC is offering a $25,000 reward for information that leads to the arrest and conviction of the person who wounded the transit worker during an attempted robbery at Dupont Station.

Investigators believe the person is responsible for two previous robberies at the same subway station.

When the reward was announced last May, police said they aren’t certain about the suspect’s gender because there have been conflicting descriptions from witnesses and surveillance video has not been conclusive.

The person was covering his or her face when the fare collector was shot Feb. 26, 2012 and when two fare collectors were robbed but not harmed in June and October of 2011.

In last year’s incident, the suspect demanded cash and pulled out a handgun, but the TTC worker did not hand over any money.

The suspect began to walk away, but turned around and fired three gunshots, striking the employee twice, police said.

The male employee suffered serious injuries.

In each case, the suspect wore similar clothing, had his or her face covered and was carrying a revolver when he or she approached the fare collector and demanded money.

A white medical mask covered the person's face during the robbery in June 2011 and he or she wore a black balaclava during the hold-up last October.

After the shooting, the TTC reviewed its security measures and began stocking boots with limited amounts of cash.

After the first two robberies at Dupont Station, the TTC changed the positioning of surveillance cameras and installed silent alarms like the one that was activated after the shooting.