Pennsylvania state police say the gun used in the Vermont shooting was purchased by a person of interest in the deaths of an elderly couple in Delaware County

Prosecutors are arguing why a Washington state woman should remain jailed in connection with the death of a U.S. Border Patrol agent

The recent murder of an 82-year-old Vallejo man may be connected to the murder of a border patrol agent in Vermont and a double homicide in Pennsylvania.

Prosecutors say a Washington state woman charged in connection with the fatal shooting of a U.S. border patrol agent had been in frequent contact with someone whom authorities have linked to homicides in Pennsylvania.

Teresa Youngblut was ordered held without bail in connection with the death of U.S. Border Patrol agent David Maland in a case that has grown to encompass killings in multiple states.

Police records show that law enforcement officials are searching for 32-year-old woman with ties to Vermont related to the purchase of the firearms allegedly used in the killing of Border Patrol agent David Maland.

By Marissa Tansino Click here for updates on this story MANCHESTER, New Hampshire (WMUR) -- Investigators said the guns allegedly

The U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives sent an alert to federally licensed firearms dealers a day after the shooting seeking information related to any gun purchases by Michelle Jacqueline Zajko.

Federal prosecutors said in a court filing that the investigation into a Border Patrol agent's shooting death has revealed a connection to Delaware County, Pa.

Associates of woman in Border Patrol agent's shooting death tied to other homicides in Pennsylvania and California.

As the sprawling investigation unfolds, here’s an overview of the key figures involved and their alleged connections.