The Aam Aadmi Party, however, called the arrest a "mere eyewash" intended at misleading the court.
The arrest comes on a day when the Delhi Police sent a notice to Delhi Chief Minister Arvind Kejriwal asking him to join the investigation in connection with the assault on Chief Secretary Anshu Prakash on February 19 at his residence.
Hussain had on February 20 lodged a complaint with the police claiming he was assaulted by officials and staff at the Delhi Secretariat, hours after Chief Secretary was allegedly attacked by AAP MLAs at Kejriwal's residence.
The Delhi Government Employees Association had, however, refuted the allegation.
A senior official said Ravinder Parmar, who is in his 50s and is an undersecretary in the Delhi Government's urban development department, was arrested. He was called for questioning a couple of times earlier and he had been named by Hussain in his complaint.
Kumar was identified on the basis of CCTV footage obtained from the Secretariat, the police said.
Kumar had already applied for anticipatory bail and after his plea was accepted he was given bail.
"The arrest of one accused ahead of the hearing in Tis Hazari court on the application moved by Hussain, is only a ploy to distract the court's attention. The murderous assault on the minister and his staff was pre-planned and the conspiracy was hatched by top bureaucrats who had provoked junior staff to carry out the attack. All these facts will be placed before the court," the party said.
In March, 11 people, including government officials, were questioned in connection with the incident.
The men were identified on the basis of CCTV footage obtained from the Secretariat.
Hussain had lodged a complaint with the police claiming that a day after the alleged assault on the Chief Secretary, he was mobbed by the officials and staff of the Delhi government who raised slogans and prevented him from taking the elevator to his 6th floor office at the Secretariat.
He said he was restrained from going to his office and his mobile phone was snatched during the incident.
The Delhi Government Employees Association had refuted the allegation and claimed that the minister had arrived at the Secretariat on February 20 when sloganeering was going on against the alleged assault on the chief secretary, but nobody manhandled him.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)