Have you seen this man? Cops say he killed ex, their 4-year-old son

If you see Jose Ronald Santos-Alvarez, don't approach him, authorities say. But they're urging anyone with information on his whereabouts to contact the Hudson County Prosecutor's Office Homicide Unit immediately.

Santos-Alvarez, 26, is wanted in the murders of his former girlfriend, Monika M. Potoczniak, 27, and their 4-year-old son, Christopher R. Potoczniak.

According to the prosecutor's office, both were found in the second-floor apartment of a Lincoln Street, Jersey City apartment last Wednesday. They were pronounced dead at a hospital shortly after.

A medical examiner determined Monika M. Potoczniak was strangled to death, the prosecutor's office said. Christopher was suffocated.

Santos-Alvarez has been charged with two counts of murder, andn arrest warrant was issued Saturday.

Authorities are asking anyone with information to contact the Hudson County Prosecutor's Office Homicide Unit at 201-915-1345 or by email at hcpotips@hcpo.org.