OCEANSIDE, Calif. -- Supporters of seven Marines and a Navy Corpsman held at Camp Pendleton in connection with the death of an Iraqi civilian picketed outside the base's main gate in Oceanside Saturday to call for their release.

Marine PFC John J. Jodka, 20, of Encinitas, and seven others are being held in solitary confinement while an investigation is conducted into the events of April 26, according to his father's Web site, innocentmarine.com.

The seven are suspected of involvement in the kidnapping and murder of an Iraqi civilian in Hamdania, a village west of Baghdad.

The demonstrators said they were upset that the Marines are being held without being charged.

"These kids haven't been charged with anything," decorated Vietnam War veteran John Sullivan told CBS2. "They haven't been convicted of anything and they are being treated worse than the guys in Gitmo."

He said the prisoners should be presumed innocent until found guilty.

"Unless you have been in those situations, you really don't have any clue what the level of stress is," he said.

The first two protesters arrived about 8 a.m., said Marine Lt. Lori Miller.

Throughout the day more people arrived and swelled the ranks, Miller said.

They shouted slogans such as "Killing the enemy is not murder," and carried signs that read "No shackles for heroes," and "Free the Pendleton 8."

"I want the Marines to know that they are not forgotten, that people are out here thinking of them," another protester told 10News.

Jodka's father set up a Web site to help raise money for his son's legal defense.

Jodka is a gunner with the 1st Squad, 2nd Platoon, Darkhorse 3/5, 1 Marine Division, according to the Web site.

The Marine Corps is assigning military defense attorneys to the eight, Maj. Jeff Nyhart told the North County Times.

Jane Siegel, who is defending Jodka, told the newspaper her client has already been assigned a military attorney, which is unusual before charges have been filed.

The Naval Criminal Investigative Service is investigating whether the eight from the 3rd Battalion, 5th Marine Regiment's Kilo Company conspired to kidnap and shoot a 52-year-old Iraqi civilian, Hashim Ibrahim Awad al-Zobaie.

No charges have been filed, but Siegel said Marine Capt. Scott Joiner told her that he had been assigned to help defend Jodka.

Jodka is the only one of the defendants to be publicly identified.

His father told the newspaper many people have voiced their support for his son.

"The comments have been overwhelmingly positive," Jodka said.

He said the families of the Marines in custody have also set up an e-mail network to support each another and share information.

"The families all seem to be doing very well and are poised for the next bump in the road," Siegel told the newspaper. "That will be the charges."

She said charges were not expected to be filed for a few days, until autopsy results are in.

Family members and friends of the Iraqi man said Marines took him from his home, shot him four times in the face and planted an assault rifle and shovel next to his body, the Washington Post reported earlier.

The Marines under investigation said in written statements that Hashim was digging a hole for a roadside bomb and was killed after a short gun battle, according to the Post.