Nicholas Brandram was arrested in June on suspicion of grievous bodily harm, after a woman was shoved in front of a bus in 2017 on Putney Bridge.
He was found dead at his home in Chiswick earlier this month.
The Met had referred itself to the Independent Office for Police Conduct (IOPC) over its contact with Mr Brandram, who was released under investigation following his arrest.
The force said on the 17th of September that its investigation into the Putney Bridge incident remains “ongoing” following the death of Mr Brandram.
Earlier today, the IOPC said: “We received a mandatory referral from the Metropolitan Police on 16 September relating to prior contact officers had with Nicholas Brandram, who was sadly declared deceased on 15 September.
“After carefully considering the referral, we have decided that an investigation is required and that the Met’s Directorate of Professional Standards should conduct it.
“We have recommended the review considers matters including the necessity and proportionality of arrest, what engagement was there with the media and considerations made in relation to Mr Brandram’s welfare and the relevant policy.
“Should the investigation conclude without identifying any potential misconduct for any officer involved, the force’s final investigation report must be submitted to the IOPC for review, to ensure independent oversight.”
