A second man has been arrested in connection with incidents of live rodents being thrown into McDonald's restaurants in apparent protests linked to the Gaza conflict.
Following a police appeal, a 30-year-old is being held in custody as part of the investigation into the "appalling" incidents in Birmingham.
The West Midlands force also said that a 32-year-old man detained earlier this week has since been bailed.
The arrests came after rodents were released at McDonald's restaurants in Regina Drive, Perry Barr, at about 1.30pm on Tuesday, and off Watson Road, Nechells, at about 5.30pm on Monday.
A third incident just before 9pm on Tuesday in Coventry Road, Small Heath, is also being investigated but may be unconnected, according to police.
Mice seen in footage
A video posted on social media on Monday showed customers at the restaurant in Nechells jumping in shock as mice dyed in the colours of the Palestinian flag scurried near their feet.
Social media posts have suggested McDonald's outlets in Israel have given 100,000 free meals to the country's soldiers and members of its security forces after Hamas launched its deadly cross-border attack on 7 October.
The reported move is said to have prompted pro-Palestinian demonstrators to boycott the global chain.
But McDonald's said at the time it was "dismayed by the disinformation and inaccurate reports" in relation to its position on the war.
A spokesperson for the chain said: "McDonald's Corporation is not funding or supporting any governments involved in this conflict, and any actions from our local developmental licensee business partners were made independently, without McDonald's consent or approval.
"Our hearts are with all of the communities and families impacted by this crisis.
"We abhor violence of any kind and firmly stand against hate speech, and we will always proudly open our doors to everyone."
In a statement, West Midlands Police said: "Our position is clear, this is appalling, and will not be tolerated.
"We will hunt down and prosecute anyone who commits such acts.
"We're stepping up patrols across the region and will be offering reassurance to our communities."