Police investigating the 7 July attacks on London have been criticised by the lawyer for Hasina Patel, the widow of suicide bomber Mohammad Sidique Khan.
A London bus and three Tube trains were targeted on 7 July
Imran Khan, who represents Ms Patel, spoke after she and two other men had been questioned over eight days and were released without being charged.
Ms Patel, 29, her brother Arshad Patel, 30, and Imran Motala, 22, were arrested in West Yorkshire and Birmingham.
Khalid Khaliq, 34, of Beeston, Leeds, is still being questioned.
Police have been granted a warrant to continue to detain him until 21 May.
The four had been held at Paddington Green police station in London on suspicion of commissioning, preparing or instigating acts of terrorism.
Mr Khan told BBC News 24 that police relations with the Muslim community have been further damaged.
"Those in her community are incredibly angry at the way the police have approached this," he said.
"In my view, if their intention in this case was to destroy what relations they had with the Muslim community, then they have done that."
He said he was "relieved" at Ms Patel's release, but remained "shocked" at the police's handling of her arrest.
He did not reveal specific details but said police had been for some time in possession of evidence that "unequivocally" proved she had known nothing about what her husband was planning two years ago.
He added: "To arrest her in these circumstances - a woman who lost her husband, who has been accused of the most atrocious events that have taken place in this country, has now spent seven days in isolation in Paddington Green - I wonder what she must be feeling.
"She's quite clearly innocent of anything, because she's been released by police having trawled through her life and possessions and caused her a tremendous amount of grief."
Fifty-two people died when Sidique Khan and three other suicide bombers attacked the London transport system on 7 July 2005.
Scotland Yard's investigation into the bombings is still continuing.
The latest arrests saw police search seven addresses in Dewsbury, Batley and Beeston, all in West Yorkshire, and Birmingham.
Last month, the first people to be charged in connection with the bombings appeared at the Old Bailey.
A spokesman said: "In all operations some people may be released early without charge while others may remain in custody for further investigation.
"This is not unusual and is to be expected in large and complex criminal investigations."