Dr. Promila Mehta-Paul, 70, was last seen on March 21. She was last seen leaving her office in Highland, Ind.
Munster, Ind., police say her 38-year-old son Paresh Paul was with the doctor on the night she disappeared. Shortly after, he left the area. He was questioned by police at the Mexico/California border which he crossed on foot.
"At that time he declined to be interviewed," said Chief of Police Stephen Scheckel, Munster Police Department. "We believe that she was met with an untimely death. We have narrowed the investigation down to him."
Police say he is still not cooperating.
Investigators say several searches of the doctor's homes lead them to believe that foul play is likely to have occurred and that her eldest son is responsible for her death. For now, he's a person of interest. Police have not announced any charges.
Officials say Paul also goes by the names of Paul Fountaine and is known to have used the aliases of Omar Ahmend and Paul Asconte.
In 2001, police were called to Mehta Paul's home because of an argument between mother and son and alleged physical abuse. Police say another son said his mother had been battered by Paresh Paul.
A police report states Dr. Mehta Paul was concerned about her son's anger management problem and did not press charges.
Police and are still looking for Dr. Mehta Paul's 2001 gold Toyota RAV 4. They believe Paresh Paul is staying in the doctor's home. Investigators are asking the public to come forward with any information about his whereabouts between March 21 and March 27.
Police say Paresh Paul has requested through an attorney to be the executor of his mother's estate.