Haynes explained that Evans, a nurse's assistant, was "overcome with emotion" while watching the demonstrations on TV and decided to take action.
She left her son behind with his father in New York and travelled to the protest site where she was taking part in the main demonstration shortly before she was arrested.
Haynes said that the fateful moment she was arrested came when officers attempted to push the crowd back from the Baton Rouge Police Department, despite the protest being peaceful until that point.
Evans told her: "I went into the street with my arms crossed and just stared at them. I guess they didn't like it because they detained me."
While Evans said that the arrest was a little rough, while in jail she said a kind officer made sure all of the demonstrators were treated well.
Police records show she was held overnight before being booked and released earlier today, and she is now in her hotel room in Louisiana recovering from her ordeal.
Evans said: "I just need you people to know. I appreciate the well wishes and love, but this is the work of God. I am a vessel! Glory to the most high! I'm glad I'm alive and safe. And that there were no casualties that I have witnessed first hand."
Evans was one of more than 100 people to be arrested in Baton Rouge on Saturday, including prominent Black Lives Matter member DeRay McKesson who was walking along the side of a highway when he was ordered to get on his knees and handcuffed.
At least two journalists were also detained during the demonstrations, the Advocate reported, while police said that two of their officers were injured, including one who lost several teeth after being struck with "a projectile".
Louisiana State Police spokesman Major Doug Cain said that in total 102 people were arrested on Saturday, with most of those being charged with "obstruction of a highway", believed to be the charge that Evans is facing.
Louisiana Governor John Bel Edwards said he was proud of how the police had handled the protests so far, saying law enforcement had responded in a "moderate" manner. He also said the vast majority of protesters had acted lawfully and nonviolently.
Edwards said, however: "It is not ... appropriate to allow them to simply block a major thoroughfare like Airline Highway."
Protesters from Louisiana or out of state will not be allowed "to incite hate and violence, to engage in unlawful activities," Edwards told a news conference. "Now I want to be very clear. That will not be tolerated."
Baton Rouge police confiscated three rifles, three shotguns and two pistols at Saturday night's protest and were wearing helmets, shields and body armour.
Police said those arrested ignored repeated orders to stay out of the street, while demonstrators said officers charged into the crowds seemingly without any obvious provocation.
"The only people who were violent last night were the Baton Rouge Police department," Mckesson told reporters after his release. "The protesters remained peaceful, both here and across the country."
