Police in La Crosse say they seized the city’s largest-ever amount of fentanyl during two recent drug investigations.  More than five ounces of the sythentic pain-killer was recovered and five suspects were arrested.  The powerful opioids have an estimated street value of 28-thousand dollars.  Investigators say Frederick B. Moore of Chicago brought fentanyl to La Crosse and sold it to an informant Tuesday.  Officers say informants purchased fentanyl twice from Lavon Liggins, and three others were arrested during an apartment search.  Fentanyl is blamed for seven possible overdoses in the last week that left five people dead.