Police want to speak to these men after a foul-smelling liquid was sprayed over the front of a family-run restaurant, leaving diners vomiting.
The incidents caused diners to suffer nausea, and emergency evacuations of the venue and surrounding area took place.
Detectives have now released CCTV showing two of three attacks on the restaurant in Brompton Road near Knightsbridge, central London, in an attempt to trace one or more suspects.
The substance, thought to be a strong-smelling food preservative, was sprayed on the front of the restaurant on the afternoon of October 30, and the nights of February 19 and February 25.
The first incident was treated as a chemical spill and saw police, ambulance and fire crews called to the scene, with 27 people evacuated from neighbouring flats as well as 15 staff who had to leave the restaurant.
During the second attack, witnesses were left with nausea and vomiting and were taken to hospital.
Detective Constable Danielle Sapsford said: “Although no serious harm has come to anyone, a number of people suffering with nausea and vomiting were taken to hospital after the incident on February 19.
“We are not in a position to completely determine motive at this stage. It does, however, appear that each incident has been targeted, and whoever is behind them must be aware of the damage they have caused to this family-run business.
“This has caused great distress to the owner and we want to bring this to an end. The most recent incident took place on a day when the owners expected the restaurant to be very busy.”
CCTV of the most recent incident shows a man in a dark coat with the hood up spraying a liquid onto the front of the shop using a syringe.
Officers have not released the name of the restaurant.
Police have also released stills of two men they would like to speak to in connection with the incident in October.
Anyone with information can call Detective Constable Sapsford by dialling 101, quoting CAD1293 of February 25, or to stay anonymous contact Crimestoppers on 0800 555 111.