“Deplorable” home conditions — dog feces on floors, insect swarms and cockroaches in a bassinet — were cited in warrants served on parents of a baby who died Wednesday.

An autopsy documented “multiple visible insect bites about (the child’s) body.” But the cause of death remained a mystery, authorities said.

Bail was set at $250,000 Thursday for Angel Ann Richardson, 21, of Ladson, whose 2-month-old son, Kayden Melvin, was in full cardiac arrest on arrival at Trident Medical Center. Richardson and Kayden’s father, Todd Stephen Melvin, 28, are both charged by the Charleston County Sheriff’s Office with unlawful conduct toward a child.

Todd Melvin’s bail was set at $150,000. Both suspects are being held at the Cannon Detention Center.

For Richardson, the death was not the first time she’s lost an infant. On June 18, 2010, Richardson’s 4-month-old daughter was found dead in the 4537 Outwood Drive home where Richardson still resides, according to County Coroner Rae Wooten.

Experts were unable to determine Mariah Benjamin’s cause or manner of death, a rarity in such cases, Wooten said.

In addition to the two infants’ deaths, Richardson faced scrutiny in 2009 for an incident involving another of her infants. In April that year, her 6-week-old baby was burned with water inside the Woodside Manor home. Richardson’s boyfriend at the time, Alexander Perry, claimed the baby suffered the burns during a bath in lukewarm water.

During that investigation, deputies found marijuana plants growing inside the house, and made charges that were later dropped.

Autopsy inconclusive Deputy Coroner Dottie Lindsay said Thursday night that the cause of Kayden Melvin’s death remains unknown.

Wooten said the boy’s body showed no obvious signs of trauma or abuse, and initial autopsy results didn’t determine how he died. But, she said, further testing could reveal the cause.

Sheriff’s Maj. Jim Brady said additional charges could be made once the cause of death is determined. The current charges deal only with the filthy conditions found when deputies alerted by the hospital searched the child’s home, he said.

Richardson and Melvin, 28, on Thursday appeared separately in bond court. Sheriff’s Detective Lauren Ryan asked Magistrate Alvin Blidgen to set significantly high bail amounts. Both are considered flight risks, Ryan said, noting that Richardson has a mother living in Baltimore.

Richardson, who shed tears while appearing in court via closed-circuit television, told Blidgen that on Tuesday she started working at KFC on U.S. Highway 78. Asked if she was on probation, Richardson said she had last been on probation as a juvenile.

Melvin said he is an unemployed fork lift operator. He told Blidgen he lives on Covington Drive although warrants served Thursday list his address as Houston Street. He told investigators he stays at the Outwood Drive home “more than three times a week,” according to the warrants.

Todd Melvin’s mother, Linda Galliard, spoke on his behalf. “He’s not really a bad boy, though he’s done some things I don’t expect out of him. He wasn’t brought up that way,” Galliard said.

In South Carolina, Melvin has been arrested seven times on misdemeanor charges, including marijuana possession, but he has no convictions, according to the State Law Enforcement Division.

Richardson does not have a criminal history, according to state records.

Investigation begins In this week’s incident, Kayden Melvin was not responding when Richardson and Melvin brought him to Nason Medical Center, according to sheriff’s reports. The boy was taken by EMS to Trident.

Warrants state the boy was in full cardiac arrest upon arrival at Trident and was pronounced dead at 10:11 a.m. Wednesday. The Sheriff’s Office was notified and launched an investigation.

Warrants allege deputies who entered the Outwood Drive home found pungent odors, swarming insects, “canine feces and unknown fluids” on the floor and several cockroaches “in the child victim’s bassinet in the bedroom that he shared with his parents.”

During an attempt to interview anyone at the home on Wednesday, flies could be seen swarming in and out of the partially opened front door. A man in the home refused comment.

A telephone line at the residence is now disconnected.

In 2009, Angel Richardson, her father Brian Allen Richardson and Perry all faced charges in connection with the marijuana deputies maintain they found in the home after the baby was scalded. The charges were later dropped.

Perry is imprisoned today on an unrelated weapons conviction.

Since late 2005, deputies have responded to the home 38 times, but Wednesday’s death was the only visit in the past two years, according to records obtained by The Post and Courier.

The calls included eight disturbances, the April 2009 child abuse and drug reports, four animal complaints, and the June 2010 infant death.

Karen Maxwell, a neighbor of Richardson’s at the time of that first death, recalled that the girl appeared to be healthy. Richardson had left to run an errand when the father found their daughter cold and unresponsive in her crib, according to Maxwell.

Cause for concernWooten said the deaths of two infants years apart in the same household naturally catches authorities’ attention.

“Obviously, we’re concerned about having two infants die in the same environment with the same folks,” she said. “There are many things we need to look at now.”

Investigators will consider all possibilities that could have led to the boy’s death, including hereditary factors, Wooten said. Experts will wait for test results before making a ruling.

“Babies very rarely die of something that we aren’t able to determine,” Wooten said. “In (the 2010) case, we didn’t know, but we were not willing to call it natural.”

Reach Edward C. Fennell at 937-5560. Reach Andrew Knapp at 937-5414 or twitter.com/offlede.