Met Police have released pictures of three men they say they want to speak to in connection with two incidents where insects were released into Byron Burger restaurants during protests. Police said the suspects entered a Byron chain in Holborn around 7pm on Friday 29 July and released locusts and cockroaches in retaliation for the company's participation in an immigration sting.

The suspects are then said to have done the same thing again at a second Byron branch in High Holborn. Both restaurants were vacated and closed.

Bryon came under heavy criticism after inviting foreign employees for a training day on 4 July, only for them to be detained by immigration officials waiting to check their documents. Thirty-five people from Albania, Brazil, Nepal and Egypt were arrested and deported in the raid.

When the news was released, protests were organised outside Byron restaurants and #boycottbyron became a Twitter trend. A Facebook statement from the group that claimed responsibility read: "Many thousands of live cockroaches, locusts and crickets [have been released] into these restaurants. We apologise to customers and staff for any irritation, however, we had to act as forced deportations such as this and others are unacceptable, we must defend these people and their families from such dehumanised treatment."

Police are asking for anyone who recognises the individuals to contact the Met's Public Order Crime Unit on 020 8246 0076. The first man is described as "dark-skinned, of medium to heavy build, unshaven with thinning hair"; the second as "dark-skinned, of thin build, with long hair – tied at the back – and unshaven"; and the third as "dark-skinned, of thin build, with short hair and a short beard".