CHICAGO -- A small vigil to remember a bicyclist who was killed by a car on Jan. 4 turned into a protest where police made four arrests.

Approximately 400 bicyclists came to the intersection of Western Avenue and Cortez Street to remember the 50-year-old bicyclist, Isai Medina, who was killed as he rode his bicycle home from work. The bicyclists were arrested for not obeying a police officer's orders. The protest briefly blocked traffic.

No charges have been filed in Medina's death, NBC5's Natalie Martinez.

"She walked up and started talking to somebody, and the next thing you know, they're handcuffing her and taking her away," said Andrew Openlander, who had to retrieve his wife from the police jail.

Naomi Gonzalez, Medina's sister, said her brother had a big heart and many friends.

"He has taken pictures with his own invention with police officers at the lakeshore," she said. "He would ride his bike from Evanston all the way to 47th (Street) south. And he was well-known. As you can see, there are over 400 bikers here."

Members of cycle groups from the area installed a white "ghost bike" to remember Medina and all other cyclists killed by motor vehicles.

"Safer streets for cyclists," said Erika Bennett, who attended the vigil. "Because it happens way, way too often. There are too many people that get hit by cars and there's not enough done (about) it."