Detectives hunting a knifeman who went berserk in a Chelmsford off-licence believe that he could strike again.

At one stage, the frenzied robber tried to reach the terrified part-time shop assistant who had locked himself in a store room to escape.

Shouting abuse, the knifeman left the Woodhall Road shop, but returned to deliver a second tirade.

He had walked quietly into the shop at about 7pm on Monday but, after the assistant had politely asked "Can I help you?" he became uncontrollable.

DS Paul Bell, who is leading inquiries, said: "We want to catch this man.

"My concern is that he could stab someone next time. This was vicious and unprovoked."

"I have never before heard of anything like this. The man just went mad.

"He hurled the till through a window, was shouting abuse all the time, waving a kitchen-type knife he was carrying and trying to trash everything in the shop.

"He carried on for about two minutes and the assistant locked himself in the store room.

"The abuse continued while he was sweeping things off the counter and breaking bottles," said Ds Bell.

"Eventually, he walked calmly out with a bottle of Cointreau and 60 cigarettes, total value £30."

The shocked 29-year-old shop assistant let himself out of the store room to ring 999 and, shortly after that, the knifeman reappeared and the frenzied abuse and vandalism began again.

The assistant locked himself away again and, after more shouted abuse and knife waving, the man walked calmly out again.

Police made a major search of the area, with uniformed officers, detectives and the dog unit all taking part.

Between £600 and £700-worth of damage was caused in the off-licence. The knifeman is described as aged between 30 and 35, slim, and about 5ft 8in tall, with short, light brown, wavy hair.

He was wearing glasses, a blue jumper and beige Chino-type trousers.

Anyone who saw the man in the area before the incident, or walking away, is asked to contact Ds Bell on 01245 491212, or Crimestoppers on 0800 555111 .

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