A family photo placed at the memorial on Danielle Drive shows Pedro Rodriguez and Deysi Benitez with their children Elsa Rodriguez, Vanessa Rodriguez, and Angel Rodriguez. The photo was date-stamped 6-14-04.

Their father, Pedro Rodriguez, 28, died of suicide by hanging, police said. Officers found Rodriguez and his four children -- Elsa Rodriguez, 9, Vanessa Rodriguez, 4, Angel Rodriguez, 3, and Carena Rodriguez, 1 -- dead in their Hillcrest townhouse March 26.

The children's mother, Deysi Benitez, 25, remains missing and hasn't been seen since March 18.

The body of Pedro Rodriguez was hanging from a second-floor banister and the children were lying in beds, covered in blankets. The children's deaths have been classified homicides, according to Lt. Tom Chase of the Frederick Police Department.

Chase declined to comment on whether any evidence in the Rodriguez home indicated what objects might have been used to kill the four children or whether police believe Pedro Rodriguez killed the children before he hanged himself.

Police have not been able to differentiate blood that may have resulted from the homicides from other bodily fluids present as a result of decomposition, he said.

Evidence at the scene conclusively determined Pedro Rodriguez's death was a suicide, Chase said, but did not elaborate.

The medical examiner's office has not completed toxicology screens, Chase said.

Examinations are still being conducted and positive identifications have not been made on all the bodies, according to the Office of the Chief Medical Examiner in Baltimore.

The office declined to discuss the causes of death for the four children because a criminal investigation continues.

Chase said police are investigating four tips about Deysi Benitez's disappearance but haven't received any additional leads on her whereabouts. He declined to comment on whether any of her personal items were missing from the home.

Investigators searched the David Park pond, across from the couple's townhouse at 1252 Danielle Drive, for nearly three hours Thursday evening but found nothing, according to Peter Gorelick, with the Frederick County Swift Water Rescue Task Force.

Chase said last week officials searched the water only because it was close to the house; they won't probe other waters unless a specific tip comes in.

Rodriguez, Benitez and Elsa emigrated from a village near Sensuntepeque, El Salvador and had legal authorization to live in the U.S. The younger three children were born in the U.S.

None of the 11 investigators on the case has been sent out of the country because no leads have come in that would justify doing so, Chase said.

Friends and relatives have said the couple was struggling financially and had marital problems. Rodriguez learned March 15 that Masonite, a door manufacturing company where he was worked since 2003, would shut down in July.

Ana Margarita Chavez, the Salvadoran consulate general in Washington, said she has not heard from the Rodriguez and Benitez families whether they want to have the bodies of Rodriguez and the four children sent to El Salvador for burial.

Victims Rights Foundation Inc., a Gaithersburg-based nonprofit organization with a Frederick chapter, is preparing to assist with burial costs should the family request help, said the organization's founder and president Gregory Wims.

-- Staff writer Nancy Hernandez contributed to this report.