Thames Valley Police is appealing for witnesses following the incident.
Between 12.10am and 12.30am on Friday (19/10) seven vehicles parked on the side of Gibsons Green were set alight causing irreparable damage.
The vehicles were empty at the time.
Officers are particularly keen to speak to a grey haired woman about 5ft 8ins tall carry what looked like a washing up bowl who was seen in the area at the time.
Investigating officer PC Lewis Jones, based at Milton Keynes police station, said: “I am appealing for anyone who may have seen or heard anything suspicious around the time of the incident or has CCTV footage that covers the area on Gibsons Green.
“I would really like to hear from the woman described above who was seen in the area at the time as I believe she may have information that is vital to our investigation.
“If you believe you have any details that may assist with this investigation, you can get in touch online quoting reference 43180319545 or by calling 101. Alternatively you can contact Crimestoppers anonymously on 0800 555 111.”
