When 23-year-old Ann Van Horn saw a Vancouver police officer preparing to pull over a friend’s black 1979 Ford Bronco one night last week, she thought it was for an equipment violation — the SUV, with large tires and a lifted frame, had no mud flaps.It was about 6:15 p.m. Wednesday. Van Horn was in her own car, a green Jeep Grand Cherokee, and her 6-month-old daughter, Isabel, was with her in a child seat. Van Horn was following her friend Jacob Conner home, not far from Marrion Elementary School, in case his 31-year-old SUV’s engine stopped running. “I noticed the cop pull out real fast as soon as he saw the Bronco,” she said.Unknown to Van Horn and Conner, it wasn’t about mud flaps.Officers in Vancouver and Hazel Dell were intently searching for a teenager who allegedly shot 19-year-old Daniel Thurston in the neck during a robbery the previous night, critically injuring him and paralyzing him from the waist down.The teen was believed to be armed with a large-caliber handgun. A witness had seen a black, older SUV like the one Conner was driving leave the scene of the 8:51 p.m. Tuesday shooting at the Parklane Apartments, 10205 N.E. Notchlog Drive in Hazel Dell.The officer who first spotted the Bronco on Wednesday night, and several more officers who were rushing to help pull it over, figured the young man driving it might be the one they were looking for — armed and willing to shoot people. Officials say the suspect had shot Thurston during a robbery involving marijuana.