Robert Levin was weeks away from running his 75th marathon when he was struck and killed by a motorist while biking in Lincoln Park this month.Levin, 61, was biking south in the 2400 block of North Ashland Avenue around 7:15 a.m. Sept. 2 when he was hit by a driver, according to his family and Chicago police.A passerby found him unresponsive on the ground and administered CPR until paramedics arrived, who then rushed him to Illinois Masonic Medical Center.Levin went into cardiac arrest upon impact with the vehicle, causing his heart to stop beating for roughly 30 minutes — depriving his brain of oxygen, said Marianne Zemil, his sister.He was pronounced dead Sept. 5 at the hospital — days from his 62nd birthday. Autopsy results were still pending Thursday.“My brother was a very outgoing, very friendly and just the kind of person who always wanted to help everyone whenever he could,” Zemil told the Sun-Times.Levin, of Rogers Park, was a devoted cyclist who didn’t own a car and rode his bike to nearly everywhere he went, his sister said. He is the second cyclist killed in a crash this year in Chicago after a 55-year-old man was struck in late August and died of his injuries nearly two weeks later.Levin was also quite philanthropic, often running in marathons for animal charities and most recently for epilepsy after his niece was diagnosed with the disorder, Zemil said. The Chicago Marathon next month would have been his 75th marathon.Known in the neighborhood as the “dog whisperer,” Levin was a certified dog trainer. He regularly walked other people’s dogs and pet-sat neighbors’ animals, Zemil said. He owned a cockapoo mix named Zelda, who now lives with Zemil’s niece, and a black cat named Winnie, who has been placed with one of Levin’s neighbors.“My brother was such an animal lover, such a giving person,” Zemil said. “It’s just mind-boggling to me that someone would leave another human being like that and not at least anonymously call for help.” Robert Levin was an animal lover, his sister said.Provided Zemil said her family feels “numb” after Levin’s death because he was the third of five siblings who have died unexpectedly. Their sister died in an accident in 2013, and their brother died from pneumonia complications last year.Detectives are continuing to investigate Levin’s death, police said Thursday.But Zemil said much of the case is still unknown to her, such as the type of car that struck her brother and the direction it was traveling. She and another family member have continuously probed detectives for more information, but have not made significant progress.“It has been frustrating because we have all this technology, all these cameras. It’s a very busy intersection,” but the camera footage has shown nothing so far, Zemil said.“Either the camera was facing the wrong way, the footage was blurry and you couldn’t see anything, one camera was broken, this other building had what appeared to be three cameras and they turned out to be decoys,” Zemil said, adding that she’s waiting to hear from police about one more surveillance camera from a nearby business.Zemil is encouraging anyone with information about the crash to submit a tip to Chicago police at cpdtip.com.“We need to know what happened,” she said.