A teenage boy was grabbed by the neck and punched in the face by two youths as he walked in Belstead Avenue, Ipswich, last Friday.
The 14-year-old was assaulted by the two teenagers at around 3.20pm, close to Luther Road.
Two men who were passing by stopped and intervened to help the victim, who was left with red marks around his neck, a black eye and a chipped tooth as a result of the assault.
Police are asking the two men who stopped to help to get in contact with officers.
Anyone who witnessed the assault or who may have any information is also asked to call Suffolk Police on 101, quoting 37/34314/16.
Alternatively, contact Crimestoppers anonymously on 0800 555 111 or through their anonymous online form at www.crimestoppers-uk.org.
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