A toddler whose remains were found inside a suitcase in Philadelphia this spring was starved to death by members of a religious cult, including his mother, in part because he refused to say "amen" after meals, police said.

Ria Ramkissoon, the mother of Javon Thompson, was charged with first-degree murder in the boy's death, and Baltimore police said that three other members of a group called 1 Mind Ministries have also been charged with first-degree murder.

Police and Ramkissoon's family say the group is a cult.

Members did not seek medical care for Javon when he stopped breathing, and the boy died in his mother's arms, according to court documents that described police interviews with a confidential informant and two children. He would have been about 15 months old when police say adults stopped feeding him in December 2006.

Ramkissoon, 21, was being held in the psychiatric ward of Baltimore's Central Booking and Intake Centre, and a bail review was postponed until Wednesday.

The three other people charged in Javon's death - Queen Antoinette, 40, also known as Toni Ellsberry or Toni Sloan; Marcus Cobbs, 21; and Trevia Williams, also 21 - were already in custody.

They were arrested in May in New York City on warrants charging them with failure to appear in court in Baltimore. Those charges stemmed from a scuffle with police in a child custody dispute.

A fifth alleged cult member, Steven Bynum, has been charged in a warrant with first-degree murder and remains at large, police said. He was believed to be in New York.

Ramkissoon's family said she should not be held responsible for her son's death. "She had no control over that situation at all," her stepfather, Craig Newton, said.

Ramkissoon's mother, Seeta Khadan-Newton, told The Baltimore Sun that it wasn't her daughter's decision not to feed the boy. "My daughter was a victim, just like my grandson," Ms Khadan-Newton said. "Somebody made that decision to not feed that child, and my daughter had to follow instructions."