The suspects were named as Muzzaker Imtiaz Shah, 24, originally from Burnley; Mustaf Jama, 25, from the north Kensington area of London, and his brother, 19-year-old Yusuf, from the same area.
PC Beshenivsky was shot last Friday while investigating an armed robbery at travel agent in Bradford.
Detective Superintendent Andy Brennan, leading the hunt for the killers, appealed for information about the suspects.
"There is no indication at this stage that any of the men have left the country," he said. "It is possible they may be in the London area. I am appealing for any information which can help us to trace these men as a matter of urgency. Do you know where they are? Can you help us?"
Police issued photographs of the three men and asked members of the public who had information to contact the incident room 01274 373700. Det Supt Brennan also disclosed more information about the movements of the getaway car.
"Immediately after the events at the travel agent, three men were seen running to a silver vehicle which was parked in Howard Street. "We believe this vehicle is the silver Toyota Rav 4 registered number WP05 YTT, details of which were provided to the media previously.
"We have trawled through many hours of CCTV and have a number of sightings of the vehicle. This includes a sighting of the vehicle travelling along Morley Street just after 3pm, only minutes before the events at the travel agent.
"The vehicle was later seen travelling along Manchester Road, out of Bradford city centre, in the general direction of the motorway network, at 3.41pm."
The SUV was hired from Heathrow airport on October 25, and is thought to have travelled north to West Yorkshire early on Friday last week.
PC Beshenivsky, who was shot in the chest, died on the day of her daughter's fourth birthday.
A memorial service was held in Bradford at 1pm today. A civic memorial service took place in the city's Centenary Square at 3.15pm, followed by a two-minute silence at 3.30pm.