The leader of a US religious cult was "outraged" when a one-year-old boy did not say "Amen" before a meal and ordered her followers to deprive him of food and water until he died, a prosecutor told jurors on Monday.

Three members of the now-defunct cult known as 1 Mind Ministries are on trial for murder in the death of Javon Thompson, who was around 16-months-old when he died of starvation and dehydration in either December 2006 or January 2007, according to authorities.

After the boy died, the cult members prayed for his resurrection, then destroyed all evidence of his death and stuffed his body in a suitcase, which they hid in a shed behind a home in Philadelphia, Assistant State's Attorney Julie Drake told jurors.

The cult members - Queen Antoinette, 41; her daughter, Trevia Williams, 22; and Marcus A Cobbs, 23 - are representing themselves at trial. Antoinette declined to make an opening statement, while Williams and Cobbs spoke briefly; Williams in a voice so quiet that jurors, prosecutors and the judge strained to hear her.

Williams suggested the prosecution's theory of the case was flawed. "Pay attention to details," she said.