Tharoor, the sole accused in the case, made the submissions through senior advocate Vikas Pahwa, who accused the agency of not disclosing the entire truth before the court.
He urged special judge Ajay Kumar Kuhar to summon the documents related to "Twitter timeline/tweets from the Twitter handle of Sunanda Pushkar".
The court sought a reply from Delhi Police on Tharoor's plea seeking documents related to Pushkar's tweets by November 15 and adjourned the matter till then.
"This is a case where cause of death is not established yet. The charge sheet took very adventurous route and wanted a psychological autopsy. But nothing has established in the case. There are rather reports which say it was neither homicide nor suicide. A psychological autopsy was conducted. They wanted to know the mental status of victim. But till date they are not clear whether she committed suicide or it was a homicide.
"The tweets clearly indicate that the deceased was not having any 'suicidal ideation' as is sought to be alleged by the prosecution. Rather, the deceased was in a positive frame of mind and was quite optimistic about her relationship with the applicant (Tharoor). Despite such overwhelming material, the police has sought to conclude that the deceased allegedly committed suicide due to her differences with the applicant," the counsel told the court.
He added that the police already had these documents and it would have been fairly considered, "there would have been no need to conduct of the psychological autopsy of the deceased, since the documents in question are in fact, direct evidence of her mental make up soon before her death".
"However, the same has been deliberately sought to be suppressed by the prosecution," he told the court.
The court had earlier urged a city court to prosecute Tharoor for abetment to suicide or "in alternative" on murder charge in the case of death of his wife.
"Please frame sections 498-A (husband or his relative subjecting a woman to cruelty), 306 (abetment of suicide) or in alternative 302 (murder) IPC against the accused (Tharoor)," the probe agency had told the court.
The police had made the submissions during arguments on framing of charges in the case.
The former Union minister, who is currently on bail in the case, was charged by Delhi Police under Sections 498-A and 306 of the Indian Penal Code.
Police had told the court that Pushkar was suffering from mental agony due to a strained relationship with her husband. She had a scuffle with her husband and had various injury marks few days before her death, they said.
Police accused Tharoor of torturing his wife which abetted her to commit suicide.
The maximum punishment for the offence listed in the charge sheet is 10 years of imprisonment. However, if convicted for 302 (murder), the maximum punishment is death penalty while the minimum is life imprisonment.
Pushkar's death had created a sensation as it came shortly after a bitter spat between the couple on Twitter over his alleged affair with Pakistani journalist Mehr Tarar.
Pushkar, 51, was found dead in a suite of luxury hotel Leela in Delhi's Chanakyapuri on the night of January 17, 2014.
The couple was staying at the hotel as the official bungalow of Tharoor was being renovated at that time.