02/04/2017 2:50 AM AEST

London Attack Arrests: All 12 People Detained Have Been Released Without Charge

All 12 people arrested in connection with the Westminster terror attack have been released without charge.

A 30-year-old man detained on March 26 in Birmingham on suspicion of preparation of terrorist attacks was released on Saturday, Scotland Yard said.

He was held on March 26, four days after Khalid Masood’s deadly attack which claimed the life of four victims, including police constable Keith Palmer outside the Palace of Westminster, the Press Association reported.

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People pay their respect at the floral memorial in Parliament Square, Westminster, London

Eleven other people previously arrested in connection with the investigation have been released without further action.

Inquests into the deaths of both Masood, 52, who was shot dead by armed police after his knife attack on Palmer, and his victims, were opened and adjourned at Westminster Coroner’s Court this week.

Pre-inquest reviews for both cases are expected to be heard at the Royal Courts of Justice on May 19.

British-born Masood, 52, drove a rented Hyundai Tucson 4X4 at speed along Westminster Bridge in a rampage which lasted 82 seconds and resulted in four deaths.

As well as Palmer, the attack also claimed the lives of Leslie Rhodes, Aysha Frade and Kurt Cochran.

Cochran’s widow, Melissa, was pictured on Friday smiling defiantly from her hospital bed surrounded by friends and family.

Melissa Cochran smiles from her hospital bed

The 46-year-old suffered a broken leg and rib and a cut to her head.

Photos were posted on a gofundme page set up to support Melissa following her husband’s death. In both she can be seen smiling.

In one image Melissa is standing with the help of her crutches with the caption: “Getting stronger every day.”

In another picture she is sat in a hospital bed, surrounded by friends and family while looking into her phone. That is captioned: “Talking with loved ones at home is some of the best medicine.”