A former friend and business partner of slain Pennsylvania mother Jennifer Brown was arrested this week for her slaying, Montgomery County District Attorney Kevin Steele announced. 

Blair Watts, 33, was taken into custody on Thursday morning and charged with first-degree murder, theft by unlawful taking, and fraudulently accessing a device. 

"For 37 days since this devoted mother was reported missing, detectives have been accumulating evidence, piece by piece, bringing into focus what happened to Jennifer and who murdered her," Steele said on Thursday. "That picture shows Blair Watts murdered Jennifer Brown on Jan. 3rd, then moved her body and ultimately buried her in a shallow grave."

Jennifer Brown

Jennifer Brown, 43, was found murdered about two weeks after she went missing last month.  (Montgomery County District Attorney)

Brown was originally reported missing on Jan. 4 by Watts, who told police that she had failed to pick up her 8-year-old son from the school bus that afternoon. 

Her son had spent the night at Watts' residence the night before on Jan. 3 to "give Brown a break," Watts told investigators. 

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A two-week search ensued and Brown's body was eventually found buried in a shallow grave behind a warehouse in Royersford on Jan. 18. A medical examiner determined that she was murdered and had three broken ribs. 

Blair Watts

Blair Watts, 33, was arrested and charged with the murder of his former business partner on Thursday.   (Montgomery County District Attorney's Office)

Before her death, Brown and Watts had planned to open a restaurant together in late January called "Birdies Kitchen" in Phoenixville. 

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Investigators found that on Jan. 3, the last day anyone saw Brown, two cash transfers worth a total of $17,000 were sent from Brown to accounts controlled by Watts. That transfer was "never part of a written agreement between Brown and Watts," the district attorney said. 

Property owners who had been in discussion to rent out their space for the duo's restaurant also told investigators that on Jan. 4, the day Brown was reported missing, Watts showed up unannounced "now saying he had money to put down on a lease."

Detectives also searched two Jeeps that were owned by Watts and his wife. A cadaver dog indicated on the backseat area of both vehicles, meaning that human remains had been in vehicles at some point. 

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Brown's son told police that he noticed Watts had his mother's cell phone on Jan. 3, which he recognized because of the phone's lock screen. 

"The movements of Watts' cell phones and the movements of Jennifer's personal cell phone show that Watts was in possession of her cell phone until it became inactive on the morning of Jan. 4," Steele said Thursday.