An investigative journalist who spent much of his career at CBS has died, The New York Times reports. Jay McMullen was 90.

McMullen’s career took him from posing as a prospective drug trafficker in Mexico to recording uniformed Boston police officers patronizing a betting parlor, the story notes. The latter story led to the demotion of several officers, the article adds.

“My ambition was to be able to feel like I was involved in some sort of service," McMullen said of his investigative work in the book "Producers on Producing," according to the story.

McMullen spent all but two years of his 37-year career at CBS, where his boss Fred W. Friendly called him "painfully slow" because of projects that could take more than a year to complete, the piece notes. McMullen joined CBS in 1949 as a writer for a public affairs TV show.