British forensic experts are in Kiev to help establish responsibility for the deaths of dozens of protesters, mostly killed by Ukrainian government snipers.
The investigators - who do not wish to be identified - say they have already pinpointed four sniper positions.
The Foreign Office declined to comment on whether the UK government was assisting in the investigation.
Ukraine's health ministry said 88 people were known to have been killed in last week's clashes.
Those killed were mostly protesters but also included police.
The British team said evidence found could be used in future prosecutions.
"It was just a bloodbath really wasn't it?" one of the investigators told BBC Newsnight's correspondent Gabriel Gatehouse.
"We're looking at the sniper positions and who would be responsible for the deaths of the people in that area."
Our correspondent said investigators had visited bullet-scarred streets just up the hill from Kiev's Independence Square, the Maidan.
By examining the trajectories of the shots fired during violence last Thursday, they had already identified four different positions from which government snipers had fired on protesters, he added.
The experts did not want to reveal their identities or who had tasked them with the investigation, saying it was a politically sensitive issue.
Meanwhile, Russia has stepped up its rhetoric against Ukraine's new Western-leaning leadership as tensions rise over the ousting of Mr Yanukovych.
Russian PM Dmitry Medvedev said interim authorities in Kiev had conducted an "armed mutiny".
And the Russian foreign ministry said dissenters in mainly Russian-speaking regions faced suppression.
Earlier, Ukraine's interim interior minister said an arrest warrant had been issued for Mr Yanukovych.
MPs voted to remove Mr Yanukovych on Saturday. His whereabouts are unknown but he was reported to have been in the Crimean peninsula on Sunday.