I found a function in this post http://softontherocks.blogspot.com/2014/11/buscar-multiples-textos-en-un-texto-con.html 
that implements the search in both ways, case sensitive or case insensitive, depending on an input parameter.

The function is:

function getMultiPos($haystack, $needles, $sensitive=true, $offset=0){
    foreach($needles as $needle) {
        $result[$needle] = ($sensitive) ? strpos($haystack, $needle, $offset) : stripos($haystack, $needle, $offset);
    }
    return $result;
}

It was very useful for me.