Thiruvananthapuram: Kerala Industries Minister E P Jayarajan on Tuesday alleged that the accused in the killing of two DYFI workers were having "close links" with a Congress MP, a charge rejected by the latter who dared the government to prove it.

Police said four people have been arrested in connection with the Sunday night incident when Mithilaj (30) and Haq Muhammed (24) of the CPIM's youth wing were attacked with sharp edged weapons at Venjaramoodu near here.

They said around eight to nine people were involved in the late night attack, suspected to be a fallout of political rivalry between the CPI(M) and the Congress workers.

A day after CPI(M) state Secretary Kodiyeri Balakrishnan alleged a high-level conspiracy by Congress leadership behind the attack, Jayarajan claimed the accused in the case have close links with Congress Attingal MP Adoor Prakash.

He demanded an investigation into the MP's role in the conspiracy to kill the two DYFI activists.

"Adoor Prakash has close links with the accused in the Venjaramood double murder case of the DYFI activists. It seems like the accused have contacted the MP through phone after the murder and his role in the conspiracy should also be probed," he told reporters after visiting the houses of the deceased.

Dismissing the charge, Prakash accused the Left party of trying to derail the probe and challenged the state government to prove it.

"The state government has the police and all the latest technology. I challenge them to prove the allegation. They must not use the police to influence the probe," he told PTI.

Meanwhile, local TV channels aired a voice clip purportedly of one of the accused alleging that Prakash had helped them in a previous case involving hacking of another DYFI worker.

Police have said they suspected rivalry between the CPI(M) and the Congress workers was the reason for the killings that triggered tension in the area on Onam day.

The two DYFI workers were attacked while they were going to Mithilaj's home on a motorbike. CCTV visuals aired by TV channels showed a gang of assailants attacking the duo.

The CPI(M) and DYFI had alleged that Congress workers were behind the killing, but the opposition party has denied any role in it saying the party "does not believe in violence".

It has given a call to observe 'black day' on Wednesday in protest against the brutal killing of the DYFI workers.

Leader of Opposition in the state assembly Ramesh Chennithala has said the Congress had no role in the killings.

"The Congress is not a party of assailants. We don't encourage goons in our party," he had said on Monday and accused the LDF government of unleashing a "false propaganda" against the opposition party.