A New Jersey man and woman have pleaded not guilty in the death of her 3-year-old daughter, who authorities believe was also sexually assaulted.

Jonathan Almodovar and Damarius Lawson were arraigned Wednesday. Passaic County prosecutors say the pair were involved in a "quasi-romantic" relationship, noting that Almodovar spent a lot of time at Lawson's home, frequently stayed there overnight and often watched her children.

The girl suffered a significant brain injury and died Jan. 26.

The 30-year-old Almodovar is charged with murder, aggravated sexual assault and child endangerment.

The 33-year-old Lawson is charged with aggravated manslaughter, child endangerment, tampering with a witness and tampering with physical evidence.

Both suspects are from Paterson and remain jailed in lieu of bail.

Their lawyers declined to comment after the arraignment.