DALLAS (CBSDFW.COM) – Friday, Billy Chemirmir sits in the Dallas County Jail accused of one murder and is believed to be a suspect in several others. Investigators, at police departments in more than one city, are looking at the 45-year-old in connection with a number of deaths. Sources tell CBS 11 News that in each case the suspect targets older women and tries to smother them.

Everything started with a Frisco police case in October of 2017. Investigators there were searching for the person who tried to kill a woman living in a retirement community.

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The 93-year-old victim told police a man had come to her door and identified himself as a maintenance worker. When she declined to have any work done the man forced his way into her home, knocked her on the ground, put a pillow over her nose and mouth and tried to suffocate her.

Believing she was going to die the woman told police she began to pray and the man stopped his assault, went into her bedroom, stole several pieces of jewelry and left.

Plano police learned of the attack in Frisco and realized the crime was similar to ones that had recently happened in their city. As a result of that investigation, Chemirmir was identified as a suspect and Plano police began following him.

During their surveillance on March 20, officers saw Chemirmir drive into the Dallas apartment complex where he lived, go to a community dumpster and throw several items in the trash. Police say when officers arrested Chemirmir, on an unrelated outstanding warrant, he had money and jewelry in his possession and when they searched the dumpster they found jewelry and a jewelry box with a name in it.

Plano police were able to trace the name to an address in far North Dallas and notified police there. When police went to the address to conduct a welfare check they found 81-year-old Lu Thi Harris dead. Harris’ name was the one associated with the dumped jewelry box.

According to a Dallas County affidavit, when Harris was found she, “…had what appeared to be lipstick smeared on her mouth and a pillow on her bed also had lipstick smears, indicating she may have been suffocated.”

Noel Crotty and her family lived next door to Lu Thi, but knew her as Kim. Crotty had nothing but kind words when describing the elderly woman. “[She was] just as generous as could be, so kind [and] always willing to give something. She always wanted to see the kids and play with them.”

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Police say a set of keys found in Chemirmir’s vehicle also belonged to Harris and “fit her front door locks.”

The Dallas arrest warrant also details the assault of a 91-year-old woman in Plano who survived an attack where, “… the suspect forced his way into the victim’s apartment, told her ‘go to the bed, don’t fight me.” When the woman complied the suspect put a pillow over her face until she passed out.

But police think Harris may not be the only person that Chemirmir has killed. CBS 11 sources say the suspect worked as a home healthcare worker and that the Collin County Medical Examiner raised a “red flag” after several older women died at a particular nursing home and all the deceased lived on the same floor.

Police in Plano held an afternoon news conference, also attended by the Collin and Dallas County District Attorneys and the Frisco police chief, where they announced the creation of a special tipline. Plano police Chief Gregory W. Rushin said, “We’re going to make every attempt to identify all the victims in the communities across the metroplex to fully investigate this case and provide justice for the victims and for their families. In an effort to accomplish this goal we’ve created a 24-hour tipline manned by our detectives at the Plano Police Department to receive calls from citizens with information relevant to this investigation.”

Police say tips called in to the h0tline — at 972-941-5785 — will be processed and provided to the appropriate jurisdiction for further investigation.

Chief Rushin said the focus will be on looking into the unattended deaths of elderly women. “We believe that the way that these crimes were committed, that when you’re a senior and you have healthcare issues and you’re living by yourself and then you do become deceased that many people would think right away that’s natural causes,” he explained. “There is not a deep investigation into those matters so it would be very easy to disguise a crime in that type of activity.”

Frisco police Chief John Bruce would not go as far as to say Chemirmir is a suspected serial killer right now, explaining that “This is early on in the investigation. We’re still trying to piece it all together and as you can see it’s a very collaborative investigation between all of these investigations.”

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Chemirmir, 45, is being held in in Dallas County Jail on a $1 million bond.