Conversation so far:
How did Homicide: Life on the Street come about?
Homicide: Life on the Street was adapted from Homicide: A Year on the Killing Streets, a non-fiction book by Baltimore Sun reporter David Simon.
What director became interested in Homicide: Life on the Street?
The film director Barry Levinson was interested in the film Homicide: Life on the Street.
What was the name of the show film director Barry Levinson was interested in?
The show is titled Homicide: Life on the Street.
What happened next with the project after film director Barry Levinson was interested in Homicide: Life on the Street?
Levinson's assistant Gail Mutrux enjoyed the book and both she and Levinson became attached as producers.

Question: Did he have to work with someone else?
Self-contained rewrite: Did David Simon have to work with someone else besides  film director Barry Levinson for Homicide: Life on the Street?