Central Industrial Security Force constable Ramnarayan Namdeo, who shot dead his senior officer Karandekar and held six colleagues hostage at the Chhatrapati Shivaji International Airport in Mumbai, was on Wednesday taken to a hospital for a psychological checkup.

"Doctors will speak to him and probe his state of mind," a senior police official said.

"During the course of our interrogation, he has expressed regrets over his surrender and claims that he would have been better off if he had shot himself after the crime.

"Namdeo wanted to speak to his colleagues. We allowed him to do so as we felt we would be able to gather some more information," he said.

However, the only line he continued to utter after seeing his colleagues was 'I have done all this for all of you', he said.

It has been reported that Karandekar was not very popular with his subordinates.

"He constantly emphasises that he had taken the drastic step to end the harassment. Through his talks, one assumes that he resorted to firing under the impression that he was representing his colleagues' cause," the official said.

Namdeo, however, now appears to be remorseful, he said.

His family claims that he was a bright student, who topped in his training classes and that he was frustrated over the 'harassment' meted out to him.