In 1979 the small town newspaper, The Point Reyes Light, won a Pulitzer for investigating the cult, Synanon.
From the paper's About page :
The Point Reyes Light is one of the few weekly newspapers to ever win a Pulitzer Prize. In 1979, when the paper's circulation was only 2,750, it received the Pulitzer gold medal for Meritorious Public Service as a result of a series of exposès and editorials about the Synanon cult. The cult was not only abusing its tax-exempt status, it had also turned to violence in an attempt to silence critics. The violence culminated in October 1978 when Synanon members tried to murder a lawyer by planting a 4.5-foot rattlesnake in his mailbox. The lawyer was bitten but survived, and The Light was the first to reveal that cult leaders had orchestrated the attack.
This happened while the paper was owned by David and Cathy Mitchell. Two people alone reporting on a dangerous cult.
I've never felt the need when in New York to seek out the Times office and stand across the street and mull its accomplishments, but I did do that when I was in Pt. Reyes.
The take away : the Mitchell's proved investigative journalism only takes an investigative journalist, not a large newspaper.