New Delhi: The stand-off between Delhi Chief Minister Arvind Kejriwal and opposition BJP over the murder of an NDMC officer intensified on Monday with the Chief Minister reiterating his demand for the arrest of BJP MP Maheish Girri while the BJP demanded that Kejriwal either prove his charges or apologize.

Kejriwal also urged Delhi Police, which does not report to him, to probe the relationship between Girri and hotelier Ramesh Kakkar, the main accused in the murder of NDMC's legal adviser M.M. Khan in mid May.

"Girri forwarded a letter written by Kakkar to the Lt. Governor asking for the removal of Khan. The LG forwarded the letter to the NDMC chairman on Girri's reference," Kejriwal told reporters here.

"Murder cases are not solved in an open debate. The police should arrest him (Girri) first and interrogate him about his relationship with Kakkar. Why did he write a letter to LG on Kakkar's behalf?"

He added: "Is this how criminal justice system works in the Modi government that whoever is accused of murder will sit on dharna outside my home?"

The Aam Aadmi Party (AAP) leader has accused the central government of shielding Girri. "He should be arrested and interrogated in the Khan murder case. Modi police shielding him," Kejriwal tweeted earlier, referring to Prime Minister Narendra Modi whose government controls Delhi Police.

Girri again denied the charges and accused Kejriwal of running a malicious campaign.

"I challenge Kejriwal and his gang of thugs to present before media and public any letter written by me to any authority on the NDMC Hotel matter or else the Chief Minister should resign," Girri told reporters.

"Kejriwal should know that I will not tolerate any nefarious attack on my image. I am a spiritual person for whom image is more important than power," he added.

The Bharatiya Janata Party also denied Kejriwal's allegations.

"We stand by our MP Maheish Girri who has never written any letter to the Lt. Governor in the context of M.M. Khan or the NDMC hotel case in question," the BJP's Delhi unit said in a statement. "All that AAP and the Chief Minister have said is a fresh bunch of lies."

Girri has been on hunger strike outside Kejriwal's residence from Sunday after the latter declined to appear for an open debate with him at the Constitution Club here.

The BJP also solidly backed Girri. Party General Secretary Kailash Vijayvargiya, the party's Rajya Sabha members Subramanian Swamy and Vijay Goel, Lok Sabha Member Manoj Tiwary and several other leaders including BJP veteran Vijay Kumar Malhotra and national vice-president Shyam Jaju joined the hunger strike led by Girri.

"I have a long spiritual bonding with Girri and I wish to tell the Delhi Chief Minister that he has rung a wrong bell and he will have to pay a heavy price for this dirty politics," Vijayvargiya said.

He also appealed to Girri to continue with the protest but reconsider his decision on hunger strike.

Swamy demanded Kejriwal's apology and also slammed Lt. Governor Najeeb Jung, saying he must be dismissed.

"There is no surprise in the way Kejriwal is acting. He is a Naxalite by nature. All allegations levelled against Girri by him are completely wrong," Swamy told party workers here.

Girri on Monday also wrote to the Delhi Police chief, asking that his role should be impartially probed.

"Probe the matter impartially and fearlessly. If you feel, please question me and if needed please arrest me," Girri said.

Khan, an estate officer with NDMC, was shot dead in Jamia Nagar here on May 16 - a day before he was expected to pass an order on the terms of the lease of The Connaught, a four-star hotel.

The hotel's owner, Ramesh Kakkar, was arrested along with six others for Khan's murder.

Both Girri and Karan Singh Tanwar, another BJP leader, have denied they are linked to Khan's murder.

Delhi Police has reportedly said they have not come across any evidence against Girri and Kanwar in the murder probe.

Girri, who represents East Delhi in the Lok Sabha, has dared Kejriwal to a public debate over the allegations and asked him to produce evidence to back the charges.