THELMA Avis only answered the "hammering" at her door because she thought someone was in need of help, her son.John Avis, 59, last night backed the re-launch of the East Anglian Daily Times' Safe in Your Home Campaign in a bid to help avoid a similar tragedy happening again.

THELMA Avis only answered the "hammering" at her door because she thought someone was in need of help, her son.

John Avis, 59, last night backed the re-launch of the East Anglian Daily Times' Safe in Your Home Campaign in a bid to help avoid a similar tragedy happening again.

The father-of-two said he only wished his 90-year-old mother had had a safety chain on her door when the callous conmen arrived on Friday evening.

An emotional Mr Avis, of Layer-de-la-Haye, described how his frail and beloved mother, who used to run an "old-time" Monkwick dancing club in the 1970s with her husband, went to the door of her house only after the knocking became persistent.

He said: "She always said she would never answer, but she told me the man kept knocking on the door. He was very persistent.

"She said he just kept hammering away and she thought maybe this was an emergency, so she opened the door.

"It seems strange because normally these kind of people don't hang around.

"She was still suspicious and followed him around. She then phoned me up, but I couldn't quite hear what she said, she was speaking so quietly so as not let the man know what she was doing.

"I thought maybe a bird had got stuck upstairs or something. When I got there, the front door was open so I picked up my walking stick that I use when walking my dog just in case.

Mr Avis described how he went upstairs and noticed a paper bag sticking out of a drawer and asked the grandmother-of-four whether she had left it like.

"She said she didn't think the man had gone upstairs," he said.

"She then burst into tears. When the police arrived, she perked up a bit – she didn't want to let them see that she was upset. But as soon as he was gone, she slumped down low again – my brother and I were worried about her.

"She seemed to be concerned about the money that had been taken and all the bills she had to pay. We tried to reassure her about things, but she wasn't feeling very well. I went to make her a cup of tea.

"She drank half of it, but then collapsed.

"It was only the fact that this man was so persistent. I can't quite believe it."

Backing the Safe in Your Home campaign, he said: "I've seen the posters in people's windows. I think it's certainly a good thing. I just wish that my mother had had a chain on her door at that time."

Housebound Mrs Avis died less than four hours after £1,000 was stolen from her home in Barn Hall Avenue, Colchester, at about 5.30pm on Friday.

Police have launched a murder investigation because they believe the trauma of the burglary could have triggered her death.

Three teenagers arrested by police in connection with the investigation into Mrs Avis' death on Monday were last night released without charge.

Officers said the trio – two from Colchester and one from Cornwall – had been eliminated from their enquiries.

A special murder hotline has been set up by Essex Police and anyone with any information should call 01277 262220 or Crimestoppers on 0800 555111.