An arrow was spotted in the middle of a road in Kirkdale after a crossbow was "fired from a window".
The weapon was slung from a block of flats on Celia Road and landed on neighbouring street Miranda Road. Officers detained a 54-year-old man before they cordoned off the area.
Homeowners and neighbours on Marsh Street, which is adjoined to Celia Road, told the ECHO they were shocked to hear the news.