The foster mother of Indian girl Sherin Mathews, found dead last month in a culvert in Dallas, has been arrested after police alleged that the Indian- American couple left the 3-year-old home alone the night before she was reported missing.

Sini Mathews and husband Wesley Mathews, who was arrested last month, went out for dinner with their biological daughter October 6, leaving Sherin because she refused to drink her milk, police in the US state of Texas said.

The 35-year-old mother, an Indian-American registered nurse, was arrested on Thursday after her attorney took her to the Richardson police station.

She is being held in the Richardson jail on a charge of abandoning or endangering a child, a state jail felony. Bail has been set at USD 250,000, police said.

A state jail felony in Texas is an offense that is punishable by confinement in a state jail facility from six months up to two years.

Police said they have not determined whether Sherin was alive when they returned home an hour and a half later, the Dallas Morning News reported.

An affidavit said the toddler was in the kitchen where they left her.

“The Dallas County Medical Examiner’s Office is continuing to work on determining the cause of death. Those results will be made available when complete,” Richardson Police said in a Facebook post.

Wesley, the 37-year-old foster father, who has since been charged in connection with Sherin’s death, remains in the Dallas County Jail on a charge of injury to a child. Bail has been set at USD 1 million. The crime is punishable with up to 99 years in prison.

Wesley had initially said he sent Sherin outside to an alley near their house about 3 am because she refused to drink her milk.

He later changed his story and to say he “physically assisted” Sherin with her milk, and admitted to removing her body from the home after she choked and stopped breathing, according to an arrest warrant affidavit.

Sherin’s death prompted External Affairs Minister Sushma Swaraj to ask the Indian Embassy in the US to be actively involved in the case and keep her informed. She also sought a probe into the adoption process of Sherin, who was adopted by the Indian-American couple last year from Bihar.

Following Sherin’s case, India decided that passports to adopted children will be issued only with prior clearance by the Ministry of Women and Child Development.