DNA results from the confirm the young male was related to the population in the Santa Monica Mountains, according to the National Parks Service.
The results show the animal shared DNA with the population north of the freeway, a finding the parks service called a "rare bright spot for a group of animals that is suffering from an extreme lack of genetic diversity."
Biologists believe the Santa Monica lion might have been the offspring of a cat known as Puma 12—the only lion they have documented crossing the 101 Freeway. The Santa Monica lion might have also crossed crossed the freeway, they said.
"In either case, the lion could have contributed unique genetic diversity to the genetically homogenous population in the Santa Monica Mountains," the parks service said in a press release.
The DNA results do not shed light on how the mountain lion managed to trek all the way to Second Street, but biologists said , when young adult male lions look for new territory to escape threats from larger male lions or to find a mate.
Seth Riley, an urban wildlife expert with the Santa Monica Mountains National Recreation Area, noted that such movements can be critical for animal populations that are penned-in by geography and development—such as the mountain lions hemmed in by the 101 and 405 freeways.
The loss and fragmentation of their habitat because of development is the biggest threat to mountain lions in the region, Riley said.
"Over the long-term, isolation of a small population of large carnivores such as mountain lions can result in inbreeding, reduced genetic diversity and even significant genetic defects," he said.
Based on information gathered from GPS collars, at least two other male mountain lions have crossed from the Santa Monica Mountains south of Sunset Boulevard.
The 95-pound animal was killed May 22 in a courtyard just a block from the after the Santa Monica Police Department and the state Department of Fish and Game attempted to sedate it using a tranquilizer dart gun.
The attempt was unsuccessful and the killing ruffled animal lovers across Los Angeles. They faulted the police department for not taking a different approach to subdue the lion.
The Santa Monica Police Department will meet with National Park Service biologists and animal rights groups later this month.
— City News Service contributed to this report.