MONTGOMERY, Ala. (AP) — A letter written by civil rights activist Rosa Parks describing the 1957 bombing of her neighbors' home has been purchased at auction by the couple who were targeted in the attack.

Alabama State University announced that the Rev. Robert Graetz and his wife Jeannie purchased the letter by Parks describing the bombing of their home. The couple plan to donate the letter to the university.

The Graetzes were among the few white supporters of the Montgomery Bus Boycott and the civil rights movement. Parks, who was the couples' neighbor and friend, sparked the boycott after refusing to give up her seat on a bus to a white passenger.

The parsonage where the Graetzes lived was bombed for the second time in 1957, not long after the boycott ended, in a wave of attacks on civil rights leaders and churches. Four black churches and the home of the Rev. Ralph Abernathy were also bombed that night.

A crude package of 11 sticks of dynamite wrapped around a small box of TNT was first thrown at the parsonage earlier that night but failed to explode. A second bomb was thrown and damaged the house. The Graetzes were at home with their children at the time.

"When the bomb detonated at 2 a.m., it blew our roof completely off of the home, as well as all of the doors; it shattered every one of the windows and did considerable other damage to the rest of our house," Jeannie Graetz said in a statement released by the university.

Parks and her husband came over to help the couple after the bombing.

Several men with ties to the Ku Klux Klan were arrested in the wave of bombings, but were not convicted.

Jeannie Graetz told the Montgomery Advertiser that the letter, in which she described the family as unharmed but badly shaken, "just reminds you of a friend that we miss."

"It's like she was just talking to us, like she was coming over to help," Jeannie Graetz said of the letter.

The family purchased the 1957 letter from New York City's Guernseys Auction for $9,375.