CENTER CITY (WPVI) -- As runners and others took to the Schuylkill River Trail for chance to enjoy a beautiful, sunny Friday and the scenery, Philadelphia police continued their search for the man behind a robbery that happened overnight."You don't really think of this as an unsafe area when you're running along here, so that's kind of shocking," said Alyssa Kirk of Rittenhouse Square.Philadelphia police say early this morning a 20-year-old man and a 21-year-old woman were walking along the trail near Walnut Street when a masked man approached them and pulled out a gun. The victims weren't injured, but the suspect ran off with their wallets and cell phones. It all happened around 12:30 a.m."We advise people if you're going to be out there you need to use extreme caution, because again it's not heavily traveled at night, so just putting yourself in the predicament it's not really the best thing to do."However, with that being said, it also doesn't give somebody the right to rob you," said Philadelphia Police Lt. John Stanford."It's beautiful down here at night. I just don't think it's the optimum safety place," said a runner who didn't want to be identified.Runners told us the sights are beautiful to take in during the day. After sunset, well, that's a different story."I wouldn't be here at that hour because it's very, very isolated, and there's so few people," said a runner who didn't want to be identified."I just think it's not safe to go anywhere lonely that late at night, no matter where you are. I just don't feel safe," said Michelle Holt of New York City.