Missouri Governor Jay Nixon has come under fire after calling for the 'vigorous prosecution' of the Ferguson police officer who shot dead unarmed black teenager Michael Brown.

The Democrat governor released a five-minute video on Tuesday, where he said: 'A vigorous prosecution must now be pursued.'

His statement began: 'Ten days ago, a police officer shot and killed Michael Brown in broad daylight. The world has watched as a community has been engulfed in grief, anger, fear, at times violence.'

The governor then called upon Attorney-General Eric Holder and St Louis county prosecutor Bob McCulloch to 'meet expectations' by finding justice for Michael Brown and his family 'thoroughly, promptly and correctly'.

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Missouri Governor Jay Nixon said in a video address on Tuesday that he wanted a 'vigorous prosecution' of Officer Darren Wilson, who shot dead unarmed teenager Michael Brown on August 9

Governor Nixon's call for the prosecution of Officer Darren Wilson comes ahead of any decisions by the grand jury who are meeting today to see if the 28-year-old will be charged.

St Louis County Prosecutor Robert McCulloch said on Wednesday that he estimated it would be the middle of October before the grand jury reached a decision on whether Officer Wilson will face charges over Michael Brown's death.

Assistant prosecutors today began presenting evidence in the shooting death. The grand jury is racially diverse, McCulloch said, with three African-Americans, according to the St Louis Post-Dispatch and was selected in May to cover the current term.

Wilson, a six-year veteran of the Ferguson force with a clean record, has not been arrested or charged with any crime.

The Missouri Governor released a statement on Tuesday calling for justice for teenager Michael Brown who was shot dead on August 9 by Ferguson Officer Darren Wilson

He is on paid leave pending the outcome of the investigation and has been in hiding due to threats over his safety.

ATTORNEY GENERAL ARRIVES IN FERGUSON TO SPEARHEAD 'FAIR AND THOROUGH' FEDERAL PROBE U.S. Attorney General Eric Holder arrived in Ferguson today where he has promised a 'fair, thorough and independent' investigation into the death of Michael Brown. President Obama ordered Holder to Missouri on Wednesday to bring the full weight of the federal government behind the investigation into the death of the black teen who was unarmed when a white police officer shot him six times on August 9. Holder has led an unusually fast and aggressive Justice Department response to the local case, sending teams of prosecutors and dozens of FBI agents to investigate and arranging a federal autopsy on top of one by local authorities. In a letter published on the St. Louis Post-Dispatch website, Holder also said the bond of trust between law enforcement and the public is 'all-important' but also 'fragile'. Arrest patterns 'must not lead to disparate treatment under the law, even if such treatment is unintended. And police forces should reflect the diversity of the communities they serve,' Holder wrote on Tuesday. He said the Justice Department would 'defend the right of protesters to peacefully demonstrate and for the media to cover a story that must be told.' Advertisement

Nixon, whose slow response to the Michael Brown shooting and over-militarization of the streets have been heavily criticized, drew outrage today following his calls for a 'vigorous prosecution'.

His deputy, Missouri Lieutenant Governor Peter Kinder, told Fox: 'It's really heartbreaking to see a man elected to an office that high in our state government ... come out with a statement like that, that does prejudge the case.

'It would be wrong for a prosecutor to say what the governor has said here tonight and it's wrong for the governor of Missouri to have said it.'

MailOnline was unable to obtain a response from the governor's office today on his remarks but a press spokesman told Fox that the governor was not prejudging Officer Wilson's actions.

Attorney-General Eric Holder arrived in Ferguson today to meet with FBI and other officials carrying out an independent federal investigation into Brown's death.

The Justice Department has mounted an unusually swift and aggressive response to Brown's death, from an independent autopsy to dozens of FBI agents combing Ferguson for witnesses to the shooting.

Wilson shot Brown at least six times, including twice in the head, after the officer stopped the 18-year-old for walking in the middle of the road shortly after noon on August 9.

The officer reportedly said Brown punched him and tried to grab his gun before charging at him.

Eye-witnesses of the shooting said that Brown had turned towards the police officer with his arms raised in surrender when he was shot dead.

Brown's shooting has sparked ten days of violent protests in the St Louis suburb. Demonstrations were significantly calmer on Tuesday but overnight, the peaceful atmosphere disintegrated amid a series of clashes that led to 47 arrests, with police claiming they were pelted with bottles containing urine.

Attorney General Eric Holder arrives at Lambert-St. Louis International Airport in St Louis on Wednesday to oversee the federal government's investigation into the shooting of 18-year-old Michael Brown

St Louis County Prosecuting Attorney Robert McCulloch (pictured on Tuesday) said today that it could be the middle of October before the grand jury will decide whether Officer Wilson will face charges

Governor Nixon also said on Tuesday that he would not seek the removal of the prosecutor overseeing the investigation into shooting of Brown.

St. Louis County Prosecutor Bob McCulloch's deep family connections to police have been cited by some black leaders who question his ability to be impartial.

McCulloch's father, mother, brother, uncle and cousin all worked for the St. Louis Police Department, and his father was killed while responding to a call involving a black suspect.

Nixon said he would not ask McCulloch to leave the case, citing the 'well-established process' by which prosecutors can recuse themselves from pending investigations to make way for a special prosecutor.

Departing from that process, Nixon said in a statement, 'could unnecessarily inject legal uncertainty into this matter and potentially jeopardize the prosecution'.

McCulloch, a Democrat, was elected in 1991 and has earned a reputation for being tough on crime.

Police officers arrest a demonstrator on Tuesday night in Ferguson, Missouri. Violent outbreaks have taken place since the shooting death of unarmed teenager Michael Brown by a Ferguson police officer

The streets of Ferguson filled once more with protesters on Tuesday evening, but the scene was much more subdued than on any of the previous five nights, with smaller crowds.

For the hours, the protest was lively but peaceful. After midnight, tensions rose as officers tried to remove the relatively small number of protesters who had not left. Several people were seen in handcuffs before most of the remaining crowd headed home.

Earlier in the day, Ferguson city leaders urged people to stay home after dark on Tuesday to 'allow peace to settle in' and pledged to try to improve the police force in the St. Louis suburb.

In a public statement, the city said the mayor, the City Council and employees have been exploring ways to increase the number of African-American applicants to the law enforcement academy, develop incentive programs to encourage city residency for police officers and raise money for cameras that would be attached to patrol car dashboards and officers' vests.

'We plan to learn from this tragedy, as we further provide for the safety of our residents and businesses and progress our community through reconciliation and healing,' the statement said.

Benjamin Crump, an attorney for Brown's family, said the 18-year-old's funeral and memorial service would be Monday. The time and location had not been finalized.

Earlier on Tuesday, a large crowd gathered in nearby St. Louis after officers responding to a report of a store robbery shot and killed a knife-wielding man. Police Chief Sam Dotson said the suspect acted erratically and told responding officers to 'kill me now'.