"He never was clinically diagnosed, but his close family and friends, we definitely knew that he was having some problems with his mood, and it kind of bound us together," Ravi, Sunil's brother told CNN.
Tripathi was on leave from Brown University, an Ivy League school, at the time of his disappearance, and had left home without his cell phone and wallet.
Sangeeta, his sister, told ABCNews.Com at the time it was "completely atypical" for her brother to vanish without contacting anyone.
"This was coming at a time, after 34 days of pain in our family, and worry, and we knew unconvincingly that this was not Sunil, especially when we saw all the video footage and surveillance that was being released," said Sangeeta.
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"It was very difficult to have the events of that night unfold so aggressively, with language that was not based on any actual evidence at all."
As part of their efforts to create positive energy surrounding their brother's disappearance, the Tripathi's have created a social media campaign entitled "Lend Your Hand," in which well-wishers inscribe messages on their skin, in hopes of ultimately finding Sunil.
After his body was recovered his family have expressed gratitude for support they received from around the world, but sought privacy in this time of grief.
"We appreciate the coverage and support, but at this time, we ask for privacy for our family and for our love for Sunny."
"As we carry indescribable grief, we also feel incredible gratitude. To each one of you - from our hometown to many distant lands - we extend our thanks for the words of encouragement, for your thoughts, for your hands, for your prayers, and for the love you have so generously shared," the family said in a message.
Tripathi, who last year suspended his studies at Brown university after enduring bouts of depression, had gone missing on 16 March.
Last week, many on social media claimed Tripathi was one of two men being sought by police over the Boston bombings. Earlier this week, editors of the Reddit social-news forum apologised for what they said turned into a "witch-hunt".