Marv Tarplin, the guitarist whose riffs and melodies helped frame the sound of one of Motown's biggest acts, Smokey Robinson and the Miracles, died on Friday (Sept. 30) at home in Las Vegas. He was 70.

A cause of death has not been determined, a rep for the Miracles said.

Tarplin brought his first-rate guitar abilities to Motown in the late 1950s as a backing musician in the Primettes, a precursor group to The Supremes. When Smokey Robinson, already with the label, formed the Miracles he plucked Tarplin and made him an original member.

Known primarily as a vocal group, he was rarely used in promotional material for the wildly popular group during its heyday. Billy Wilson of the Motown Alumni Association called him the group's "secret weapon" in comments picked up by the BBC.

"You can't express how much this one man meant to those of us dreaming to make it in the music business," Wilson said. "His creative backbeat rhythms on guitar allowed the powers that be to find the creative juices to formulate what would become major classic hits for Motown."

As a songwriter, Tarplin co-wrote Miracles hits including "Tracks of My Tears," "My Girl Has Gone" and "The Love I Saw in You Was Just a Mirage." Although "Tears" was not one of the Miracles' biggest charting songs, it is widely regarded as one of their finer moments and was covered by the likes of Aretha Franklin and Linda Ronstadt, who made it a Top 40 hit in 1975.

He later collaborated with Robinson on solo hits such as 1979's "Cruisin" and "Being With You." He also co-wrote songs for other Motown artists, including Marvin Gaye and The Four Tops. Tarplin continued touring with Robinson until he retired in 2008.

Tarplin is survived by three daughters. His wife, Sylvia, died in 2004.