[HIGHLIGHTS] The Manhattan District Attorney's Office is preparing to file charges against the former Marine who suffocated Jordan Neely in the New York subway

Daniel Penny, 24, is accused of strangling Jordan Neely, 30, to death on May 2. Neely was dressed as Michael Jackson and had mental health issues.

Penny is expected to be charged with second-degree murder and criminal possession of a weapon. The case is under investigation by the New York City Police Department and the NYPD's Department of Law and Disorderly Conduct. The DA's office has not released a motive for the incident. The NYPD says it is investigating the death of Neely and his family.