Lalbazar: A Facebook post by city police on Wednesday announced a reward of Rs 50,000 each for information leading to the arrest of five "dangerous" suspects in a robbery case that has been unsolved since April.

The post on the police's official Facebook page has pictures of the men who had allegedly robbed a Posta trader of Rs 14.4 lakh. It also carries a warning. "The suspects are of dangerous nature. Please do not take undue risks. Merely passing on the information to us is enough."

The police had pasted these pictures on walls near Liluah railway station after learning that the robbers might be residents of the area.

"Police stations across the city are already on the lookout for the suspects. We will share the pictures with our counterparts in the districts and also the railway police," said an officer in the detective department.

On the afternoon of April 7, the gang entered a five-storey building on Kali Krishna Tagore Street and barged into the office of Devi Lal Sharma on the mezzanine floor. They took away Rs 14,48,000 at gunpoint from an employee named Shyam Sharma and also assaulted him.

In his statement to the police, Shyam said three men had entered the office. Investigators suspect the other two gang members were standing guard.

The pictures being used by the police to trace the gang are screenshots from CCTV footage. A camera installed at the entrance to the building, which houses the offices of more than 30 traders, caught the gang entering and exiting with the loot.

Devi Lal, who deals in grapes from Nasik, no longer operates from that office. "He opened his office on a few occasions only for the purpose of the police investigation," said a trader who uses office space on the third floor. "We came to know about the incident after the police entered the building on the evening of the incident."

The Facebook post titled "Wanted by Calcutta Police", states: "Anyone having information about any of the above suspects may contact us at the following phone numbers and he/she shall be rewarded (with) a sum of Rs 50,000 for any such authentic information. The identity of the informant will be kept secret."

The city police had last announced a reward of Rs 50,000 for information about suspects in a dacoity at Beniapukur in 2017.