Jury selection for the criminal trial of Daniel Penny, a U.S. Marine Corps veteran charged with manslaughter for putting a deadly chokehold on subway performer Jordan Neely aboard a New York City train last year, began in Manhattan on Monday.

The court proceedings against Penny, 25, are expected to last six weeks, according to the Associated Press. Penny is regarded by some New Yorkers as a White vigilante who caused the death of Neely, 30, a Black man. Others have applauded Penny’s actions and hailed him as a “good Samaritan.”

Penny was charged after protesters and lawmakers called for his arrest after a video of him holding Neely in a chokehold for at least three minutes was widely disseminated. Neely was pronounced dead at a hospital, and the death was ruled as a homicide caused by compression of the neck.

Here’s what to know about the trial.