Death of a professor: "Too much of insufficient evidence"

From this very distressing report:

Nearly three years after he was allegedly beaten to death, six Akhil Bharatiya Vidyarthi Parishad (ABVP) activists accused of the murder of Prof HS Sabharwal in Ujjain, Madhya Pradesh, were today acquitted by a Nagpur court due to lack of evidence.

[...]

Public prosecutor Praful Shandilya said that there was "too much of insufficient evidence" when the case was transfered from Ujjain to Nagpur. He said he had made an application for further investigations in the case, as relevant material which could lead to a conviction had not been collected by the investigating agency.

"The investigating agency is under the state and there were allegations against the political party ruling the state. So it [state government] got it executed in the manner it wanted," Shandilya said. [Bold emphasis added.]

And the report adds that "ABVP lawyer Pushpendra Kaurav said the prosecution had failed to establish that the accused were at the site of the incident."

How can we understand this failure when "the assault was shown repeatedly on national TV, with two of the main men even circled to identify them," as Dilip points out?